Overnight Brioche French Toast Casserole

This overnight brioche french toast casserole is made by layering slices of buttery brioche bread in a casserole dish and soaking them in an egg and buttermilk mixture overnight. It’s topped with an oat streusel and baked to perfection. Throw it together at night and pop it in the oven the next morning. It’s a perfect breakfast for special occasions and lazy weekends alike!

My son, who just graduated from high school, came home from work and said he was bragging to his boss about this casserole. It’s such an easy breakfast, but it wows even the teenagers enough to talk your cooking up to the boss. 🙂

Why You’ll Love French Toast Casserole with Brioche

• Prepare French toast casserole the night before to save time in the kitchen. Then, enjoy a stress-free morning with a ready-to-bake breakfast!
• The oat streusel topping adds the perfect crunch texture to compliment the soft custardy base.
• Ideal for feeding a crowd, making it a go-to option for holiday gatherings and weekend brunch.

What will I need to make this overnight breakfast casserole?

You will need the following ingredients:

• Eggs
• Buttermilk
• Light brown sugar, dark will work too.
• Vanilla extract
• Ground nutmeg
• Brioche bread
• All-purpose flour
• Rolled oats
• Ground Cinnamon
• Salt
• Salted butter
• Syrup
• Fruit for topping (optional)
• Powdered sugar for topping (optional)

You will need the following supplies:

• 9×13 casserole dish
• Mixing bowls
• Mixing utensils
• Measuring utensils
• Aluminum foil
• Pastry cutter

How to Make French Toast Casserole with Brioche

1. Spray a 9×13 casserole dish with nonstick spray. Cut brioche bread slices into fourths, layer the cubed bread in the bottom of the pan, and set aside.

2. In a large mixing bowl, whisk together eggs, buttermilk, brown sugar, vanilla extract, cinnamon, and nutmeg until well combined.

3. Pour the mixture evenly over the bread and lightly press the bread down into the egg mixture to help cover it in eggs. The bread will continue to soak up the egg mixture as it sits. Cover with aluminum foil and refrigerate overnight for 6 hours. When ready to bake, remove the casserole from the refrigerator, let it sit on the counter for 30 minutes, and preheat the oven to 350ºF.

4. To make the oat crumble topping, add flour, oats, cinnamon, brown sugar, and salt into a medium mixing bowl and mix until combined. Add cold cubed butter and cut the butter in using a fork or pastry cutter until the mixture is crumbly. Sprinkle evenly over the casserole. This can be made the night before and added in the morning.

5. Cover the casserole dish with aluminum foil and bake at 350ºF for 45 minutes. Remove foil and bake for 10-15 more minutes until the top is golden brown.

Note: When you remove the foil and continue baking, butter may settle into the uneven parts of the casserole. Tilt the casserole dish back and forth to spread it out, and then continue baking for 10-15 minutes uncovered.    

This Overnight French Toast Casserole recipe is the perfect choice for Christmas morning, Easter brunch, Mother’s Day breakfast, or even your regular weekend mornings. Serve it with warm maple syrup and a sprinkle of powdered sugar for a delightful treat the whole family will love.

FAQs

How to store Brioche French Toast Casserole.

To store brioche French toast casserole, make sure it’s completely cooled before transferring it to an airtight container. The casserole can be stored in the refrigerator for up to three days. If you want to keep it longer, you can freeze it for up to two months, just be sure to wrap it tightly in plastic wrap and foil before freezing. When you’re ready to enjoy it again, thaw it in the fridge overnight and reheat it in the oven until warm.

Why does Brioche French Toast Casserole need to sit overnight?

This casserole is best when it sits overnight. It allows the bread to soak up all the egg mixture and the flavors to meld together, making for a better result. However, if you are short on time, this casserole can be baked after sitting for 30 minutes.

What if I don’t have buttermilk?

If you don’t have buttermilk, you can easily make a substitute. Simply add 1 tablespoon of lemon juice or white vinegar to 1 cup of milk and let it sit for 5-10 minutes. This will create a slightly thickened, tangy mixture similar to buttermilk. 

Can I substitute another dairy option for buttermilk?

Yes, you can substitute another dairy option for buttermilk, such as heavy cream, half-and-half, or whole milk. You can also use a dairy-free alternative if needed. Keep in mind that the recipe was specifically tested with buttermilk, so the final results may differ slightly in taste or texture when using a substitute.

Why does the casserole need to wait 30 minutes before baking?

Letting the casserole sit for 30 minutes before baking allows it to come closer to room temperature, which helps it bake more evenly and reduces the overall cooking time. This also helps prevent thermal shock, which can cause a cold dish to crack when placed in a hot oven.

Do I have to add the crumble topping?

The oat crumble topping adds a nice crunch and sweetness to your French toast casserole. However, you can bake the casserole without it, especially if you prefer a simpler or less sweet dish. Keep in mind the recipe’s overall sweetness was balanced with the crumble in mind, so omitting it might slightly alter the overall flavor.

What sides go well with brioche French toast casserole?

Brioche French toast casserole is great on its own, but if you want to add some sides, there are plenty of tasty options. Fresh fresh berries or bananas is a great way to add some fresh produce. If you’re craving something savory, try serving it with crispy bacon or sausage.