Overnight Blueberry French Toast Casserole

This Overnight Blueberry French Toast Casserole is the ultimate breakfast or brunch dish—easy to prep the night before and bursting with juicy blueberries, warm cinnamon, and rich vanilla custard. It’s baked to golden, fluffy perfection with a buttery streusel topping for a sweet, slightly crispy finish. Whether you’re hosting a holiday brunch or just want a no-fuss weekend treat, this make-ahead casserole is guaranteed to impress.

🛒 Ingredients

1 loaf of French bread or brioche (cut into 1-inch cubes)
1½ cups fresh or frozen blueberries
8 large eggs
2½ cups whole milk (or half-and-half for richer flavor)
½ cup heavy cream
⅓ cup granulated sugar
⅓ cup brown sugar
1 tablespoon vanilla extract
1 teaspoon cinnamon
½ teaspoon salt

For the Streusel Topping

½ cup all-purpose flour
½ cup brown sugar
1 teaspoon cinnamon
¼ cup cold butter, cubed

🔄 Substitutions

Bread: Use challah, sourdough, or gluten-free bread
Blueberries: Substitute with raspberries, blackberries, or chopped apples
Milk/Cream: Use dairy-free milk and coconut cream for a non-dairy version
Sugar: Maple syrup or coconut sugar can be used in place of brown/white sugar
Butter: Use vegan butter or coconut oil in the streusel

👨‍🍳 How to Make

Grease a 9×13-inch baking dish and layer cubed bread evenly in the dish
Sprinkle blueberries over the bread cubes
In a large bowl, whisk together eggs, milk, cream, sugars, vanilla, cinnamon, and salt until smooth
Pour the custard mixture evenly over the bread and blueberries
Cover tightly with foil or plastic wrap and refrigerate overnight (or at least 6 hours)
In a small bowl, mix flour, brown sugar, and cinnamon. Cut in the cold butter with a fork or pastry cutter until crumbly. Cover and refrigerate
In the morning, preheat oven to 350°F (175°C). Sprinkle the streusel over the casserole
Bake uncovered for 45–50 minutes or until golden and set in the center
Let cool slightly before serving. Dust with powdered sugar and drizzle with maple syrup if desired

🧁 Mix-ins

Chopped nuts like pecans or walnuts
Lemon zest for a bright citrus note
Cream cheese chunks for added richness
White chocolate chips for a decadent twist

✅ Recipe Tips

Use day-old or slightly stale bread—it soaks up the custard best
If using frozen blueberries, do not thaw before adding to prevent sogginess
Cover loosely with foil while baking if the top browns too quickly
Let sit for 10–15 minutes after baking for easier slicing

📦 Storage

Refrigerator: Store leftovers in an airtight container for up to 4 days
Freezer: Freeze baked casserole in portions for up to 2 months
Reheat: Warm in the microwave or oven at 325°F (160°C) until heated through

🌀 Recipe Variations

Peach French Toast Casserole: Swap blueberries for fresh or canned peaches
Cinnamon Roll Style: Add swirls of cinnamon-sugar between layers
Pumpkin Spice Version: Add ½ cup pumpkin purée and pumpkin spice to the custard
Savory Twist: Omit blueberries and sugar, add cheese, herbs, and cooked bacon or sausage

❓ FAQs

Can I make this the same day?
Yes! Let it soak for at least 1 hour if you’re short on time—overnight still gives the best texture

What kind of bread is best?
Brioche, challah, or French bread hold up best and soak in the custard without getting mushy

Can I use almond milk or oat milk?
Absolutely. Just be sure it’s unsweetened so you can control the flavor and sweetness

Do I have to make the streusel?
It’s optional, but it adds a beautiful crunchy top—definitely recommended!

Soft, warm, and bursting with blueberry flavor, this Overnight Blueberry French Toast Casserole is a make-ahead marvel that makes breakfast feel extra special—without extra effort. Perfect for holidays, weekends, or anytime you want to treat yourself and your guests!