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Overnight blueberry French toast casserole topped with fresh blueberries and powdered sugar
Tiffany

Overnight Blueberry French Toast Casserole

This Overnight Blueberry French Toast Casserole combines buttery brioche, juicy blueberries, and a vanilla-cinnamon custard under a crisp brown sugar streusel. Assemble it the night before, refrigerate, and bake it in the morning for an easy holiday or weekend brunch.
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Prep Time 20 minutes
Cook Time 50 minutes
Chilling Time 8 hours
Total Time 9 hours 10 minutes
Servings: 8 servings
Course: Breakfast, Brunch
Cuisine: American
Calories: 485
Ingredients Equipment Method Notes

Ingredients
  

French Toast Casserole
  • 1 tablespoon unsalted butter for greasing
  • 1 loaf brioche or challah bread about 14 ounces, cut into 1-inch cubes
  • 2 cups fresh or frozen blueberries divided
  • 8 large eggs
  • 2 cups whole milk
  • 1/2 cup heavy cream
  • 1/3 cup pure maple syrup
  • 1/4 cup packed light brown sugar
  • 2 teaspoons vanilla extract
  • 1 teaspoon ground cinnamon
  • 1/4 teaspoon ground nutmeg
  • 1/2 teaspoon kosher salt
  • 1 teaspoon lemon zest
Brown Sugar Streusel
  • 1/2 cup all-purpose flour
  • 1/2 cup packed light brown sugar
  • 1/2 teaspoon ground cinnamon
  • 1/4 teaspoon kosher salt
  • 6 tablespoons cold unsalted butter cut into small cubes
  • 1/2 cup chopped pecans optional
For Serving
  • Powdered sugar optional
  • Maple syrup optional
  • Fresh blueberries optional

Equipment

  • 9×13-inch baking dish
  • Large mixing bowl
  • Medium mixing bowl
  • Whisk
  • Measuring cups and spoons
  • Aluminum foil

Method
 

  1. Grease a 9×13-inch baking dish with the tablespoon of butter.
  2. Arrange half of the bread cubes in the prepared baking dish. Sprinkle with 1 cup of blueberries, then add the remaining bread and blueberries.
  3. In a large bowl, whisk together the eggs, milk, heavy cream, maple syrup, brown sugar, vanilla, cinnamon, nutmeg, salt, and lemon zest.
  4. Slowly pour the custard mixture over the bread. Gently press the bread down with a spatula so it absorbs the liquid.
  5. Cover the baking dish tightly and refrigerate for at least 8 hours or overnight.
  6. To prepare the streusel, combine the flour, brown sugar, cinnamon, and salt in a medium bowl. Cut in the cold butter with a fork until coarse crumbs form. Stir in the pecans if using.
  7. Cover the streusel and refrigerate it separately overnight.
  8. The following morning, remove the casserole from the refrigerator and let it stand at room temperature for 20–30 minutes.
  9. Preheat the oven to 350°F. Sprinkle the cold streusel evenly over the casserole.
  10. Cover the baking dish loosely with aluminum foil. Bake for 30 minutes.
  11. Remove the foil and continue baking for 20–25 minutes, until the top is golden and the center is set. A knife inserted near the center should come out without liquid custard.
  12. Allow the casserole to rest for 10 minutes before serving.
  13. Dust with powdered sugar and serve warm with maple syrup and fresh blueberries, if desired.

Notes

Slightly stale brioche or challah absorbs the custard better than very fresh bread and helps prevent a soggy casserole.
Fresh or frozen blueberries may be used. Do not thaw frozen blueberries before adding them.
The casserole should chill for at least 8 hours so the bread can absorb the custard evenly.
If the top browns too quickly, loosely cover the dish with aluminum foil during the final minutes of baking.
The casserole is ready when the center is set and no liquid custard is visible. Baking time may vary slightly depending on the depth and material of the baking dish.
Store leftovers in a covered container in the refrigerator for up to 3 days. Reheat individual portions in the microwave or warm the covered baking dish in a 325°F oven.