The intoxicating scent of cinnamon-spiced sourdough transforming into a custardy masterpiece filled my kitchen when I first tested this egg-free Sourdough French Toast Casserole recipe. The tangy notes from the sourdough perfectly balance the sweet, velvety corn starch-thickened custard that soaks into each slice, creating those crispy edges we all fight over at Sunday brunch.
Whether you’re accommodating dietary restrictions or simply ran out of eggs, this make-ahead sourdough French toast casserole delivers all the comfort of traditional French toast with a delicious twist.
👩🏽🍳Why You Should Make This Egg-Free Sourdough French Toast Casserole
- Perfect Make-Ahead Breakfast Solution
Prepare this easy French toast casserole the night before and simply pop it in the oven the next morning for a stress-free breakfast that's perfect for busy weekday mornings or relaxed weekend brunches without the morning rush. - No Eggs, All Flavor
This innovative egg-free version delivers all the custardy goodness of traditional French toast without compromising on that perfect texture—making it ideal for those with egg allergies or when you've simply run out of eggs. - Sourdough Advantage
The natural tanginess of sourdough bread creates the perfect flavor counterpoint to the sweet custard, preventing the dish from becoming too sweet while adding complexity that regular bread just can't match. - Meal Prep Champion
This casserole reheats beautifully, making it perfect for batch cooking—prepare once and enjoy delicious breakfasts throughout the week with minimal effort. - Customizable Canvas
The base recipe serves as a perfect foundation for endless variations—add fresh berries, chocolate chips, nuts, or a streusel topping to create a new experience each time you make it. - Ultimate Comfort Food Upgrade
The combination of crispy edges and soft, custardy centers delivers that satisfying textural contrast that makes comfort food so irresistible, elevating a simple breakfast into something truly special.
🧂Ingredients and Substitutions
Sourdough Bread
My homemade cinnamon sourdough bread works perfectly here, but any sourdough sandwich bread with a firm texture will shine in this egg-free French toast casserole. Day-old bread actually works better as it absorbs the custard without becoming soggy. If you can't find sourdough, challah or brioche can substitute nicely, though you'll lose some of that distinctive tangy flavor that makes sourdough French toast casserole special.
Butter
I use unsalted butter to control the salt content, but salted butter works in a pinch—just reduce any additional salt in your recipe. For dairy-free options, coconut oil or plant-based butter alternatives provide similar richness. European-style butter with higher fat content creates an extra luxurious custard if you're feeling indulgent.
Corn Starch
This is the magic ingredient that thickens our custard without eggs! For egg-free sourdough French toast, corn starch creates that perfect custardy texture. Arrowroot powder or tapioca starch can be substituted in equal amounts if you're avoiding corn products. Always mix the starch with a small amount of cold milk first to prevent lumps in your custard.
Vanilla Extract
Pure vanilla extract adds wonderful depth to breakfast casseroles. In a pinch, vanilla bean paste offers gorgeous flecks throughout your custard, or try almond extract for a subtle twist. I recommend avoiding imitation vanilla, as the flavor doesn't hold up to baking as well.
Ground Cinnamon
Ceylon cinnamon has a more delicate flavor perfect for breakfast dishes, though standard cassia cinnamon works beautifully too. For different flavor profiles, try adding a pinch of nutmeg, cardamom, or ginger alongside the cinnamon—these warming spices elevate any overnight French toast casserole.
Whole Milk
The fat content in whole milk creates a rich custard base for our egg-free French toast. For a dairy-free or vegan version, full-fat coconut milk or oat milk make excellent alternatives. Using half-and-half or adding a splash of heavy cream can make your sourdough breakfast casserole even more decadent for special occasions.
Brown Sugar
The molasses content in brown sugar adds wonderful caramel notes to this make-ahead French toast casserole. Light or dark brown sugar both work well—dark simply provides a deeper flavor. Coconut sugar or maple syrup can be substituted for different flavor dimensions, though liquid sweeteners may require slight adjustments to the milk quantity.
🔪Step-by-Step Instructions
Step 1: Making the Egg-Free Custard
Start by combining all your custard ingredients in a microwave-safe bowl – milk, cornstarch, brown sugar, vanilla, and cinnamon. Whisk thoroughly until the cornstarch is completely dissolved to prevent any lumps in your finished custard. Now add the butter cubes. Pop the mixture into the microwave for 1 minute, then remove and whisk vigorously. The mixture will begin to thicken slightly, but we're not done yet! Return to the microwave for another minute, remove and whisk again (this intermediate whisking is crucial for a smooth custard), then microwave for a final minute. If you're using chilled butter, you'll need the full 3 minutes, but room temperature butter might only require 2 minutes total. Your finished custard should be smooth and thick enough to coat the back of a spoon. Allow the custard to cool slightly before proceeding to prevent the bread from becoming too soggy.
Step 2: Soaking the Sourdough Bread
Cut sourdough bread into cubes of your choice. Arrange your homemade sourdough bread cubes in a greased 9 inch baking dish, overlapping them for the perfect casserole texture. Pour your warm custard evenly over the sourdough bread pieces, making sure to get some in between each bread piece.
Press the bread down gently to help it absorb the liquid. For the best flavor development and texture in your sourdough French toast casserole, cover the dish and refrigerate overnight – this allows the bread to fully absorb all those wonderful flavors. In a pinch, 4 hours will work, but the overnight soak really transforms this breakfast treat into something spectacular. This is a great make ahead recipe.
Step 3: Baking Your Casserole
When you're ready to bake, preheat your oven to 350°F (175°C). Remove your sourdough French toast casserole from the refrigerator while the oven heats up, allowing it to come to room temperature for about 20 minutes. Bake uncovered for 25-30 minutes until the casserole begins to puff up and the edges turn golden brown. Then, cover loosely with foil for the final 10 minutes to prevent over-browning while ensuring the center cooks through perfectly. The finished egg-free French toast casserole should have crispy edges with a custardy, tender center – the ultimate textural contrast!
Step 4: Serving the Sourdough French Toast Casserole
Once baked to golden perfection, allow your casserole to cool for 15 minutes – this resting period helps the custard set up for cleaner slicing. Drizzle generously with sweetened condensed milk for a decadent finish, or get creative with maple syrup, fresh berries, cream cheese frosting, or a dusting of powdered sugar.
This make-ahead sourdough breakfast casserole is perfect for serving at brunches or holiday gatherings since everyone can customize their toppings. Leftovers (if you have any!) can be refrigerated and reheated in the oven for a quick breakfast throughout the week.
📝Recipe Notes & Troubleshooting Tips
- Getting your egg-free sourdough French toast casserole just right is all about understanding a few key details. For the perfect texture, dry or day-old bread works best as it absorbs the custard without becoming mushy. If you only have fresh sourdough bread, slice it and leave it out uncovered for a few hours or lightly toast it before assembling.
- The cornstarch in this recipe needs proper heating to activate its thickening powers. If your custard seems too thin after microwaving, continue heating in 30-second intervals, whisking between each, until it coats the back of a spoon. For those without a microwave, you can prepare the custard on the stovetop over medium heat, whisking constantly until thickened.
- Don't rush the soaking process! The overnight refrigeration isn't just for convenience—it allows the flavors to meld and the bread to fully absorb the custard. If your casserole turns out dry, you likely didn't soak it long enough or your bread-to-custard ratio was off.
- For a dairy-free sourdough breakfast casserole, substitute the whole milk with full-fat coconut milk or oat milk and use a plant-based butter. The thickness of your alternative milk matters—if using a thinner plant milk, you might need to add an extra teaspoon of cornstarch.
- If the top of your casserole browns too quickly during baking, don't panic! Simply tent it with foil earlier in the baking process. Conversely, if you want more caramelization on top, brush the surface with a little melted butter before baking or sprinkle with additional brown sugar during the last 10 minutes.
- For an even more decadent make-ahead French toast bake, consider adding a streusel topping before baking or folding in fresh berries between the bread slices. Just be sure any add-ins like berries are patted dry to prevent excess moisture from making your casserole soggy.
- Remember that gluten-free sourdough can be substituted, but it typically absorbs less moisture, so you may need to reduce the custard amount by about ¼ cup. And if you're serving this for a special occasion, try preparing individual egg-free sourdough French toast cups in a muffin tin for a stunning presentation that bakes in just 20-25 minutes!
🫙Storage Instructions
Let's talk about saving that delicious easy French toast casserole for later (though I totally understand if there aren't any leftovers)! Proper storage means you can enjoy this breakfast treat for days after you make it.
Refrigerator Storage: Once your casserole has completely cooled, cover it tightly with plastic wrap or aluminum foil, or transfer portions to an airtight container. Your egg-free French toast casserole will stay fresh in the refrigerator for up to 4 days. The flavors actually continue to develop overnight, making day-two casserole sometimes even better than fresh from the oven!
Freezer Storage: This sourdough breakfast casserole freezes beautifully! For best results, let it cool completely, then either freeze the entire casserole or cut into individual portions. Wrap tightly in plastic wrap, then aluminum foil, and place in a freezer-safe bag or container. Label with the date – it will maintain its quality for up to 3 months. Individual portions are perfect for quick weekday breakfasts when you need something special without the effort.
🔥Reheating Instructions
- Reheating from Refrigerated: For the best texture when reheating refrigerated leftovers, preheat your oven to 325°F (165°C) and warm individual portions for about 10-15 minutes or until heated through. Cover with foil to prevent further browning and drying out. If you're in a hurry, the microwave works too – just heat in 30-second intervals until warmed through, though you'll lose some of that wonderful crispy texture.
- Reheating from Frozen: You can reheat frozen portions directly without thawing, though it will take longer. For the oven method, keep the casserole covered with foil and bake at 325°F (165°C) for about 20-25 minutes, then uncover for the last 5 minutes to restore some crispness. For an extra touch of freshness, add a sprinkle of cinnamon or a drizzle of maple syrup just before serving your reheated sourdough French toast casserole.
Pro Tip: If you know you'll be freezing portions, slightly underbake the original casserole by about 5 minutes. This prevents the reheated portions from becoming dry or overdone.
With these storage tips, your make-ahead sourdough French toast casserole truly lives up to its name – ready to bring comfort and deliciousness to your breakfast table whenever you need it!
❓Frequently Asked Questions
Absolutely! This sourdough French toast casserole is the perfect make-ahead breakfast option. In fact, the recipe is designed to be prepared in advance, as the overnight soak allows the bread to fully absorb the custard mixture, resulting in that perfect texture – crispy on top and custardy in the middle. To prep ahead, simply assemble the entire casserole, cover it tightly with plastic wrap or foil, and refrigerate overnight or for at least 4 hours.
You can prepare it up to 24 hours in advance, which makes it ideal for holiday mornings or when hosting brunch. The next morning, just remove it from the refrigerator while your oven preheats (allowing it to come to room temperature for about 20 minutes), then bake as directed. This advance preparation actually improves the flavor as it gives more time for the cinnamon and vanilla to infuse throughout the sourdough bread.
If you're really planning ahead, you can even freeze the unbaked casserole for up to 1 month – just thaw overnight in the refrigerator before baking.
Leftover sourdough bread elevates French toast casserole in several significant ways that make it worth seeking out specifically for this recipe.
1. The natural tanginess of sourdough creates a beautiful flavor contrast with the sweet custard, preventing the dish from becoming overwhelmingly sweet like some breakfast casseroles can be. This balance of flavors creates a more sophisticated breakfast experience.
2. Additionally, sourdough's sturdy structure holds up remarkably well when soaked in liquid, maintaining its integrity rather than dissolving into mush. This results in that perfect textural contrast between the crispy top and custardy interior that makes French toast casserole so irresistible.
3. The fermentation process in sourdough also breaks down some of the gluten, making it easier to digest for many people.
4. And because sourdough has a lower glycemic index than regular white bread, your breakfast casserole provides more sustained energy throughout the morning without the quick blood sugar spike and crash.
5. Finally, the distinctive holes and texture of sourdough artisan bread allow it to absorb the custard mixture more effectively, creating pockets of creamy goodness throughout so that you get the best overnight French toast casserole.
🔗 Suggested recipes
- Cinnamon Crunch toast
- Sourdough French Toast Recipe
- Oreo French Toast
- Danish breakfast buns
- Brioche Cinnamon rolls
- Sourdough pancakes
- Pumpkin pancakes
- Ube cinnamon rolls
- English Muffins
This egg-free overnight sourdough French toast casserole has become my weekend brunch staple, combining the tangy complexity of sourdough with a perfectly custardy texture that'll have everyone asking for your secret.
I'd love to see your creations - snap a photo of your make-ahead breakfast masterpiece and tag me on Instagram, or leave a comment below sharing how you customized this recipe to make it your own!
Sourdough French Toast Casserole
Equipment
- 9 Inch Casserole
Ingredients
- 6 slices of sourdough bread
- 3 tablespoon Butter (unsalted)
- 1 tablespoon corn starch
- 1 teaspoon vanilla
- 1 teaspoon ground cinnamon
- 1 ½ cup whole milk
- ¼ cup brown sugar
- ¼ cup of condensed milk for serving (optional)
Instructions
Step 1: Making the Egg-Free Custard
- Combine all custard ingredients in a microwave-safe bowl: milk, cornstarch, brown sugar, vanilla and ground cinnamon.
- Whisk thoroughly until the cornstarch is fully dissolved to prevent lumps.
- Add butter cubes to the mixture.
- Microwave for 1 minute → remove and whisk vigorously.
- Microwave again for 1 minute → remove and whisk again (crucial step).
- Microwave for a final 1 minute (especially needed if using chilled butter). Note that the room temperature butter might only need 2 minutes total.
- Finished custard should be: Smooth and thick enough to coat the back of a spoon.
- Let the custard cool slightly before using to avoid soggy bread.
Step 2: Soaking the Sourdough Bread
- Cut sourdough bread into cubes of your preferred size.
- Arrange the cubes in a greased baking dish, overlapping each other slightly.
- Pour warm custard evenly over the bread cubes, ensuring it gets between pieces.
- Press the bread down gently to help absorption.
- Cover and refrigerate.* Best: Overnight for deep flavor and perfect texture. * Quick version: At least 4 hours if short on time.
Step 3: Baking Your Casserole
- Preheat oven to 350°F (175°C).
- Remove casserole from the fridge and let sit for about 20 minutes at room temperature.
- Bake uncovered for 25–30 minutes until the edges turn golden brown
- Cover loosely with foil for the final 10 minutes to prevent over-browning and ensuring the center cooks evenly.
- Final texture should be slightly crispy edges, custardy, tender center – the perfect contrast!
Step 4: Serving Your Sourdough French Toast Casserole
- After baking, allow casserole to rest for 15 minutes to help the custard set.
- Serve with sweetened condensed milk (for a decadent finish), or get creative with maple syrup, fresh berries or powdered sugar.
Notes
- Nailing the texture of an egg-free sourdough French toast bake starts with choosing the right bread. Day-old or slightly dried sourdough is ideal, as it soaks up the custard without falling apart. If you're working with fresh bread, let the slices air-dry for a few hours or lightly toast them to firm them up before layering.
- Activating cornstarch properly is key to getting that luscious custard. If your mixture still seems runny after microwaving, continue heating it in short 30-second bursts, whisking well after each, until it thickens enough to coat the back of a spoon. No microwave? You can easily cook the custard on the stove over medium heat—just stir constantly until it reaches the right consistency.
- Give it time to soak! That overnight rest in the fridge isn't just about saving time in the morning—it's what allows the bread to fully absorb the custard and develop rich, cohesive flavor. A dry casserole usually means it didn’t soak long enough, or there wasn’t quite enough custard to go around.
- Making it dairy-free? You can swap the whole milk with full-fat coconut milk or creamy oat milk, and replace the butter with your favorite plant-based option. Just keep in mind, thinner plant milks may need a little extra help—try adding an extra teaspoon of cornstarch to thicken things up.
- Watching the top brown too quickly? Just loosely cover your casserole with foil partway through baking to protect it. If you're aiming for more of that golden, caramelized finish, brushing the top with a bit of melted butter or sprinkling brown sugar in the last few minutes of baking will give it a gorgeous, toasty look.
- Looking to level up? A simple streusel topping adds crunch and decadence, or you can tuck in some fresh berries between the bread slices for a fruity twist. Just make sure to pat any fruit dry first—too much moisture can lead to a soggy casserole.
- Using gluten-free sourdough? No problem, but keep in mind it tends to soak up less liquid. Try cutting the custard back by about ¼ cup. For a festive touch—especially for brunches or special mornings—bake the casserole in muffin tins for adorable, single-serve portions that cook in about 20 to 25 minutes.
Mike
I love how it combines the tangy flavor of sourdough with a sweet, custardy base—without the need for eggs.