This luscious overnight french toast bake is full of juicy blueberries and topped with crunchy brown sugar cinnamon streusel. It’s one of my favorite ways to use stale sourdough bread while also making a serious dent in the eggs on my counter!

If you like this french toast casserole, you might also like my Spinach and Cheese Croissant Strata.

Blue casserole dish with blueberry french toast

Table of Contents

What You’ll Need
How to Make Overnight Blueberry French Toast Casserole
How can I tell when my casserole has finished baking?
How to Store and Reheat Leftovers
Get the Recipe

If you’re looking for an easy & indulgent way to use a stale loaf of sourdough bread, this overnight french toast bake is just the ticket. I can’t say enough good things about this recipe. It has the perfect balance between crunchy streusel topping and soft, bready bits soaked in sweet custard. I’ve used this recipe to transform even the hardest loaf of forgotten sourdough (or french bread) into a breakfast/brunch treat.

Bonus: You can prepare the entire french toast casserole the night before and then bake it first thing in the morning. Your home will smell amazing! Just add maple syrup and whipped cream for the most addictive breakfast ever. Every time I make this casserole my family starts calling dibs on leftovers before breakfast has even begun.

Blueberry french toast bake in a casserole dish with a slice taken out

What You’ll Need

Here are the ingredients for this easy french toast casserole. Be sure to scroll down to the recipe card below for specific amounts.

For the French Toast:

Unsalted butter
Crusty sourdough or French bread – Stale bread works best for this. If you buy a loaf for this recipe I recommend leaving it out overnight to dry out a bit.
Fresh blueberries – You can use other kinds of fresh fruit, such as raspberries, blackberries and strawberries. Feel free to do a mix! Just keep the total amount about the same.
Eggs – This recipe uses 8 eggs! Huzzah!
Milk – I use whole milk but you could also use lowfat or plant milk.
Brown Sugar – Light or dark.
Vanilla extract
Freshly grated nutmeg

For the Topping:

All-purpose flour
Brown sugar – Both light and dark brown sugar will work.
Ground cinnamon
Kosher salt
Cold unsalted butter – This recipe uses a whole stick of butter for the struesel. Is that calorie dense? Sure! But let’s be honest, a really good french toast casserole is not going to be health food. I have no regrets. 🙂
Maple syrup & whipped cream – For serving

A slice of french toast casserole in front of a blue baking dish

How to Make Overnight Blueberry French Toast Casserole

The night before:

Grease your baking dish with butter.

Mix the bread and blueberries. Cut the bread into 1-2 inch cubes and add to your pan. Add the blueberries and gently toss to mix together.

Make the custard & add to bread. In a large bowl whisk together the eggs, milk, sugar, vanilla, and nutmeg. Pour over the bread and blueberries.

Make & add the topping. In a medium bowl, combine the flour, sugar, cinnamon, and salt. Mix together. Add the butter and use your fingers to combine everything together, firmly pressing the flour mixture and butter pieces together until you have something that resembles coarse breadcrumbs. Sprinkle this mixture over the top of your bread and blueberry mix.

Cover tightly with saran wrap and refrigerate overnight.

The morning of:

Heat the oven and bake. In the morning, preheat your oven to 350F. Take the casserole out of the fridge and remove the plastic wrap. Bake for 50 minutes to 1 hour, until the custard is set. You can check this by gently cutting into the casserole. You shouldn’t see any runny liquid.

Keep an eye on it. After 40 minutes check your french toast bake and if it is browning too quickly you can cover it loosely with aluminum foil to give the custard time to set without over-browning the dish.

Cool. When done, allow the casserole to cool for 15 minutes.

Serve. Then scoop out individual portions and serve with maple syrup, whipped cream and additional blueberries if desired.

Pouring maple syrup on a slice of french toast casserole

How can I tell when my casserole has finished baking?

The best way to tell if your french toast bake has finished cooking is to make a small cut down the center with a sharp knife. If you see liquidy custard still, the casserole has not finished baking.

If the outside of the casserole is already browned nicely when you check for doneness you can loosely cover it with aluminum foil and return it to the oven. This way the insides can finish baking without the top over-cooking. Add additional bake time in 8-10 minute increments to avoid over-baking.

Slice of blueberry french toast bake with syrup and whipped cream

How to Store and Reheat Leftovers

Allow your french toast casserole to come to room temperature, then cover it with saran wrap or transfer it to an air-tight container and store it in the fridge. It will keep for up to 4 days.

When you are ready to eat some, just cut off a slice and reheat it in the microwave. For large slices, I will usually cut it into half so that the inside warms through. The amount of time required to reheat will depend on how big your slice is. I recommend opting for small to medium-sized slices.

Filed Under:

This post may contain affiliate links. Please read our disclosure policy.

Overnight Blueberry French Toast Bake