There’s not one word more perfect than “unbelievable” to describe this overnight blueberry french toast casserole. Perfect make-ahead recipe for busy mornings!

Now THIS is french toast! Made with chunks of crusty bread, sweet blueberries, lots of brown sugar, a sweet egg-y custard, assembled in a baking pan, and topped with brown sugar cinnamon streusel.
There’s enough goodness to make your entire family happy. And then some.

This casserole is the definition of comfort food. I made it for my friends who just welcomed their daughter into the world. I prepped the french toast the night before and brought the dish to them the next morning after baking it for about 45 minutes. That’s the beauty of this breakfast… it’s designed to be made ahead of time.
It’s designed to MAKE LIFE EASIER!
I typically use challah bread when I make french toast—either in traditional form or as a casserole. It’s my favorite when making berries & cream french toast also. Although you can use sourdough bread or french bread like I use for mini french toast. Homemade or store-bought, whichever is easiest. Even homemade honey-oat bread would be fantastic. No matter what type of bread you use, make sure it’s crusty. Day-old and a little stale. Bread that’s been sitting out a day or two (and therefore has lost some moisture) will absorb much more of the egg custard.
Speaking of the egg custard. What you’ll make is a thick mixture of eggs, milk, brown sugar, vanilla, and cinnamon. 1/2 teaspoon of cinnamon will go into the custard AND in the streusel on top. The cinnamon soaking into the bread is phenomenal!
For that creamy custard taste, I use 8 eggs total and a little over 2 cups of whole milk. Whole milk is key; I don’t suggest a lower fat milk. Even half-and-half would do. You want a luxurious, thick custard.

You’ll cut the bread up into cubes, pour the custard overtop, and stick the whole pan in the refrigerator. During this time, the crusty bread soaks up the cinnamon spiced egg custard, imparting flavor and moisture into the dish as a whole. You can leave it in the refrigerator anywhere from overnight down to 3-4 hours. I find the longer the bread soaks, the tastier the casserole. So, put the refrigerator to work!

During the last few minutes of fridge-time, prepare a brown sugar streusel topping. This is like icing on the cake—like the best parts of crumb coffee cake + French toast combined. The streusel topping is made from equal parts brown sugar and flour, a dose of cinnamon, and cold butter. Emphasis on the cold! The butter is cut into the other 3 ingredients using a pastry blender. Alternatively, you can use two forks or even your fingers.
Sprinkle it over the soaked bread and bake until golden brown. This is the kind of breakfast you make on the weekend not only to gobble up with friends and family, but to smell it as it bakes. I always thought baking banana bread was the best aroma from the oven but this… oh man. It’s even better.

There’s so much texture and flavor, but I think the best part of this overnight french toast is the juicy blueberries. They pop and burst, leaving sweet blueberry juice in between all the cracks and crevices of the casserole.

Fill your plate and top it all with maple syrup, butter, fresh fruit, homemade blueberry sauce topping, or a shower of confectioners’ sugar. There’s no wrong way to eat this unbelievable goodness! Just as long as you go back for seconds.
Print
Unbelievable Blueberry French Toast Casserole
- Prep Time: 25 minutes
- Cook Time: 50 minutes
- Total Time: 9 hours, 30 minutes
- Yield: serves 12
- Category: Breakfast
- Method: Baking
- Cuisine: American
Description
There’s not one word more perfect than “unbelievable” to describe this overnight blueberry french toast casserole. Perfect make-ahead recipe for busy mornings!
Ingredients
- 1 (12-14 ounce) loaf french bread, sourdough bread, or challah*
- 1 cup (180g) fresh or frozen blueberries*
- 8 large eggs
- 2 and 1/4 cups (540ml) whole milk
- 1/2 teaspoon ground cinnamon
- 3/4 cup (150g) packed light brown sugar
- 1 Tablespoon (15ml) pure vanilla extract
Streusel Topping
- 1/3 cup (69g) packed light brown sugar
- 1/3 cup (41g) all-purpose flour (spooned & leveled)
- 1/2 teaspoon ground cinnamon
- 6 Tablespoons (86g) unsalted butter, cold and cubed
- optional: extra blueberries, fresh fruit, maple syrup, and/or confectioners’ sugar for topping
Instructions
- Grease a 9×13-inch pan with butter or spray with nonstick spray. Slice then cut the bread into cubes, about 1 inch in size. Spread cubes into the prepared baking pan and top evenly with blueberries. Set aside.
- Whisk the eggs, milk, cinnamon, brown sugar, and vanilla together until no brown sugar lumps remain. Pour over the bread. Cover the pan tightly with plastic wrap and stick in the refrigerator for 3 hours – overnight. Overnight is best.
- Preheat oven to 350°F (177°C). Remove pan from the refrigerator.
- Prepare the topping: Whisk the brown sugar, flour, and cinnamon together in a medium bowl. Cut in the cubed butter with a pastry blender or two forks. Sprinkle the topping over the soaked bread.
- Bake for 45-55 minutes or until golden brown on top. I usually bake it for 45 minutes because I like it softer. Serve immediately. Cover leftovers tightly and store in the refrigerator for 2-3 days.
Notes
- Make Ahead & Freezing Instructions: Prepare the topping in advance, cover tightly, and store in the refrigerator. Sprinkle over the soaked bread before baking. For freezing, prepare the recipe through step 4 (without preheating the oven) and freeze for up to 2 months. Thaw overnight in the refrigerator then bake as directed. Baked casserole can be frozen up to 3 months. Thaw overnight in the refrigerator and warm up in a 350°F (177°C) for 35 minutes or until warm in the center.
- Special Tools (affiliate links): 9×13-Inch Baking Pan | Glass Mixing Bowls | Whisk
- Half Batch: This recipe can easily be halved in an 8-inch baking pan or 9-inch baking pan. The bake time will be slightly less, around 30-35 minutes.
- Bread: Day-old, crusty bread is perfect for french toast casseroles. I typically use a loaf of challah bread that I slice and let sit out overnight. You’ll wind up with about 12 cups of cubed bread. A little more or less is OK.
- Fruit: Instead of blueberries, try strawberries, raspberries, or blackberries. In the fall, try cranberries or thinly sliced apples or pears. So many options!
Keywords: overnight french toast casserole, blueberry french toast casserole

Made this for our Christmas Eve brunch – everyone loved it! Said it was so good. Such a time saver too to make it the day before!
Amazing! This casserole was the hightlight of my buffet! Everybody loved it and I will be making it again! Great (small) leftovers this morning and good cold. Thank you!
My daughter can’t have dairy. Would this recipe work with almond milk
Yep, should be fine.
I’ve made this at least three times already and it is always unbelievable. I do use dark brown sugar since it’s my weakness, but besides that everything is the same. Thanks so much!
I had almost a pound of leftover, slightly freezer-burned bread taking up precious freezer space, but I felt bad wasting it, so I tried this recipe out. Sooooo good, as always! I used frozen mixed berries and 2c nonfat milk + 0.25c half and half since I didn’t have anything else. The outside came out chewy and caramellized while the inside stayed creamy and custardy. Definitely will make again!!!
This was delicious! Made this for family that stayed overnight. All I had to do is put it in the oven in the morning. I did add walnuts to the topping. May add some orange or lemon zest to egg mixture next time just for a bit more flavor but really this was perfect the way it was. Company loved it and went back for seconds. Thanks again for a wonderful recipe.
You’re welcome, Penny! I love things I can make the night before when I have company. And it would be great to try to lemon or orange zest!
Made this for Easter Brunch. Everyone loved it. So delicious. I will definitely make this again and again.
My daughters graduating grad school and we are celebrating. Having a big brunch and trying to make it easier with as much make ahead and freeze dishes as I can. Which way will it be better? Cook and freeze or prepare and freeze? I can do both. Thanks
Honestly I’ve done both ways, but prefer cooking THEN freezing.
Sooooo good! I’ve made several other blueberry French toast recipes but none compare to this 🙂 Not too sweet either with just the right hint of cinnamon and sugar. That streusel topping is key!!!!! Love, love, love this recipe 🙂 Thanks Sally!!!!
Hi. Would raisin bread work well with this ?
Yes, definitely!
I have lots of rolls and croissants left over from Christmas, can those be used?
Absolutely!
I’m seeing that it looks somewhat soupy before it bakes. Is this normal?
Yep!
I made this just as the recipe was written…….but I added about a tablespoon of grated lemon zest. Everyone LOVED it!!
I made this for Mother’s Day brunch, used a loaf of chocolate chip brioche, sprinkled with blueberries. So delicious, mom and family loved it. Thanks!
We love this french toast casserole! I make a loaf of challah in the bread machine, cut it and leave it out overnight. The next day I prepare the casserole and let it sit overnight in the fridge and we eat it on the third day. It’s delicious and my whole family love it! Today I’m assembling one and putting it in the freezer as one of my “get ready for baby #4” meals. It’s sweet and flavorful enough on its own that it doesn’t need syrup! MY family request this often and we’ve even had it for dinner a few times! Thanks for an amazing recipe!
I made this last week for my family and they loved it. Instead of doing it over night, I made it in the morning and had it for supper. I also combined your two french toast recipes, so there was a cream cheese layer with blueberries. It was awesome…even the left overs tasted good! By the way, I am a distant relative in Michigan. Your grandma passed out your cook book at a family coffee. I enjoyed looking at it.
I’ve made this recipe several times, and everyone always loves it! My stepmother said “this might be the best thing I ever put in my mouth”! high praise, and it goes all to you!
Hi Sally, I have cubed (generous sized cubes) a lovely challah loaf; about 14oz. I have them in sort of 2 layers in a ~7×11 Pyrex dish drying out for the next few hours. Do you rec’d that I do a single layer to bake? Or can I leave it in this dish and will it bake up just fine in 2 layers? Thanks in advance!
Btw, I made several of your cookies over Christmas – every single one was just delish, as always! Thank you for bringing your readers just the very best.
Two layers is completely fine, Faye. I have no fear the about the french toast casserole; it will be wonderful. You might need to add a couple extra minutes to the bake time though!
What can I say except…WOW. Made this for Christmas brunch at a lake home for six people Easy and delicious I made a mistake and made this with skim mIlk (had half-and half but was so tired when I prepped this I forgot about it!). Woke up at 2:00a.m. Thought I had ruined it but knew it was too late. Turned out great anyway. Making it for New Year’s brunch (at the same lake place) and will use the 1/2 and 1/2. Made a blueberry syrup which was the perfect complement. Definitely a keeper!
Sally, I am planning on making this tonight, do I need to thaw the frozen blueberries before?
Thanks!
No need to thaw them.
Must this have the streusal topping?
I’m afraid of it being too sweet.
You can leave it off!
I’m making this for Father’s Day Sunday Brunch! One questions…when you cut the cold butter, is it supposed to be chunky or liquid? I feel like that is going to be the hardest part for me.
Make sure there are some chunks of butter.
Hi Sally! I actually had leftover challah bread from the weekend that was a bit old and therefore didn’t go as well as it usually does….so I made this casserole for breakfast today 🙂 YUM! Only problem is, my struessel topping seems to get messed up during cooking. It kindof melts together and turns really dark and hard looking instead of looking like crumbs (still TASTES great though). Any thoughts of what I could be doing wrong?
Is your butter very cold and is the streusel broken up into small crumbs? It sounds like the streusel is melting too much, too quickly. Try frozen butter. That should help!
For the streusel, did you melt the butter? I just made mine and after combining flour, cinnamon, brown sugar and butter it wasn’t much of a liquidy mixer to pour on the bread. It was thick so I used a brush to spread it over the bread. I did use dark brown sugar so I don’t know if maybe that was the difference or not.
It needs to be cold and cubed, then cut in.
Made this for my son’s rowing meet yesterday and everyone LOVED it! Added diced banana to the blueberries and used half&half instead of whole milk. Doubled the recipe, using 2 loaves of challah and baked for an hour. HUGE HIT with the kids and the parents…seems I have found my staple item!!
This recipe is a keeper! I made the casserole for Easter brunch and it was a huge hit. My daughter asked how many eggs I used because she noticed it wasn’t dry like some other recipes I’ve tried. I added an extra handful of blueberries. Also used French bread which worked fine. Will try it with Challah bread the next time because there will be a next time!
Made this last night for my coworkers today. Everyone raved about it! I’m usually not a big French toast person…but I think I may have been converted. Thanks!
Hi Sally,
Happy Friday! Can I cut the recipe in half? I would only want 6 servings?
Yep! In an 8 or 9-inch square pan.
If your guests have problems with whole milk, would almond milk work. Any other suggestions.
Whole milk is preferred for its rich and creamy texture in the custard. Keeping that in mind, almond milk should be fine.
Just finished devouring this, and it was delicious! I used French Bread but I can’t wait to try it with Sourdough, or Challah if I can get my hands on it!