Let’s Talk About Overnight Blueberry French Toast Casserole

You know those mornings when you wake up, totally craving something sweet and comforting, but the idea of flipping pancakes or fussing with eggs is just, nope? Yeah, me too. That’s when I pull this overnight blueberry french toast casserole trick out of my sleeve. First time I made it, I was honestly just trying to clean out the fridge after a long weekend—old bread, half a bag of blueberries, and a hope that the kids would actually eat breakfast without complaint for once. Spoiler: they went back for seconds. Bonus: it’s the only way I get to sip my coffee before it goes cold (sometimes, anyway!).

Why I Keep Making This (and You Might Too)

I make this when I’ve got folks coming for brunch, but also when I just want to pretend I have my life together—because you whip it up the night before and in the morning it’s practically magic. My family goes crazy for this because of the crispy edges and pops of blueberries (my son tried picking them all out once… he failed, obviously). Sometimes I double the cinnamon, sometimes I don’t even measure—nobody’s ever complained either way. And, oh, if you’ve got someone who “doesn’t do” French toast, this is my secret weapon.

What You’ll Need (and What I Sometimes Swap)

1 loaf day-old bread (brioche, challah, or even just sandwich bread—whatever’s malingering in your bread box, honestly)
1 1/2 cups fresh or frozen blueberries (I’ve been known to pull out the wild ones from the freezer—worked fine)
8 large eggs (medium eggs work, just subtract a splash of milk, or add one more if you like it extra custardy)
2 cups milk (whole is ideal, but I’ve used half-and-half or oat milk in a pinch—don’t tell my aunt, she thinks that’s sacrilege)
1/2 cup cream (optional but, come on, why not?)
1/2 cup granulated sugar (sometimes I use brown sugar for a bit more depth, though it’s really not fancy)
1 tablespoon vanilla extract (artificial or real, I won’t judge—I’ve used both depending on what’s left in the bottle)
1 teaspoon cinnamon (my grandmother was heavy-handed, so sometimes I get a little wild and double it)
Pinch salt (roughly half a teaspoon—a real pinch, not the dainty kind)
For topping: 1/3 cup cold butter (cubed), 1/3 cup flour, 1/3 cup brown sugar, more cinnamon (if you feel like it)

Let’s Get This Casserole Going (Directions)

Start by greasing a 9×13 inch baking dish. Honestly, I just rub a bit of butter around with a bit of paper towel—no time for pastry brushes.
Cube up that bread into bite-sized chunks, about an inch or so. If there’s crusts, I leave them on—more texture, less waste. Scatter half in the dish, throw a handful of berries in, then cover with the rest of the bread and the rest of the berries. (Sometimes I forget and just dump everything together. No disasters yet!)
In a big bowl, whisk together eggs, milk, cream, sugar, vanilla, cinnamon, and salt. Nothing fancy—just bash it all together with a fork or a whisk. Pour this mixture evenly over the bread. Maybe give things a gentle press so everything gets a nice soak.
Cover tightly—foil, clingfilm, whatever—and pop it into the fridge overnight. Or at least 6 hours. (I once left it for almost 24. It was fine. Actually, I think it tasted better, but maybe I was just hungrier.)
Next morning, preheat oven to 350°F (175°C). While it’s heating, make your crumb topping: smush the cold butter, flour, brown sugar, and cinnamon together with your fingers until you’ve got nice little lumps. Sprinkle it over the casserole. Don’t fret if it looks uneven—it’ll all come together in the oven.
Bake for about 45-55 minutes, or until puffed and golden on top. If the top browns too fast, loosely cover with foil. (This is where I usually sneak a taste from the corner—chef’s privilege!)
Let it cool for ten minutes or so before serving. Or don’t—I’ve burned my tongue more than once because patience just isn’t my strong suit.

Things I’ve Figured Out (Notes)

If your bread is really fresh, try toasting it in the oven for a bit—otherwise you might get a slightly soggy bottom (ha!).
I once used only frozen blueberries and didn’t bother thawing. That works. Just add a few minutes to baking time if it seems underdone in the middle.
Actually, I find it works better if you let it sit uncovered for the last 10 minutes to crisp up the topping.
Don’t panic if the custard looks too jiggly at first—it sets up more as it cools.

Variations I’ve Messed With (Some Worked, Some… Not So Much)

Swapped blueberries for blackberries and strawberries—lovely, though strawberries made it a bit soggy. Not my fave, honestly.
Added lemon zest to the custard once; really brightens things up. If you’ve got an extra lemon, go for it.
Tried chocolate chips instead of fruit (kids thought it was dessert, which, to be fair, it almost is).
Skipped the crumb topping once. Regretted it. Don’t do that!

What You’ll Need in the Kitchen (Plus MacGyver Options)

9×13 inch baking dish. If you don’t have one, a couple of smaller glass dishes work—just keep an eye on the baking time.
Big mixing bowl (though I’ve used a soup pot in a pinch—nobody died).
Foil or clingfilm for overnight chilling, but if you forget, a big plate works too. Gets a bit of a fridge funk, but hey, it’s breakfast.

Keeping and Reheating (If You Have Any Left)

Covers well in the fridge for up to three days, honest, but in my house it never lasts more than a day—unless I hide a portion behind the mustard. To reheat, I bung a slice in the microwave or back in the oven for 10 minutes at 350°F. Once I tried freezing it in portions; wasn’t bad after a quick oven reheat, although the crumb gets a little moody and soft.

How I Like to Serve This (And Some Family Quirks)

We’re big on pouring maple syrup all over it (the real stuff, if the budget allows). I sometimes do a dusting of powdered sugar because it looks fancy, even if we’re still in pyjamas. For special brunches, I’ll set out bowls of yogurt or whipped cream and just let everyone go wild. Not that anyone ever complained about having too many options at breakfast.

Things I Learned the Hard Way (Pro Tips From Mess-Ups)

Don’t skimp on soaking time—it’s tempting to stick it right in the oven, but I once tried rushing this step and regretted it (dry spots and a sad face at breakfast).
Cutting the bread too big? Won’t soak up enough custard. Too small? Just gets mushy. But don’t stress—mediumish is best.
If the crumb topping gets super dark too quick, just chuck some foil over it but not too tight or it’ll get steamed up, trust me.

Questions People Actually Asked Me About This (FAQ)

Can I make this dairy free? I’ve subbed in almond milk and used coconut cream—tastes a little different, but still gets polished off.
How do I keep it from getting soggy? Use older bread, or toast fresher stuff. But honestly, a little gooeyness in the middle is kinda nice.
Can I bake it right away? Sure, you can, but I think it’s way better if it sits overnight—the flavors get cozy.
Do I really need the crumb topping? Well, need is a strong word, but… yes. You want it. Trust me on this one.
Can I prep more than a day ahead? Yup, I’ve done it up to 36 hours before. Just stir the custard before pouring if it separates.

Just don’t forget the coffee, or tea if that’s your thing. And hey, if you look up and realize you’ve eaten half the pan straight form the dish—no judgement here. We’ve all been there!

Overnight Blueberry French Toast Casserole Recipe for Breakfast Bliss