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Blueberry French Toast Casserole

Overnight Blueberry French Toast Casserole with Streusel

This make-ahead casserole features rich, cubed French bread soaked overnight in a cinnamon custard, layered with fresh blueberries, and topped with an optional brown sugar streusel, perfect for a stress-free holiday brunch.
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Prep Time 15 minutes
Cook Time 55 minutes
Total Time 1 hour 10 minutes
Servings: 8 servings
Course: Breakfast, Brunch, Dessert
Cuisine: American, Comfort Food
Calories: 310
Ingredients Equipment Method Notes

Ingredients
  

I. French Toast Base and Custard
  • 1 loaf French bread, Challah, or Brioche Day-old, cut into 1-inch cubes (about 8-10 cups)
  • 8 Large eggs
  • 2 cups Whole milk Or half-and-half for richer custard
  • 1/2 cup Granulated sugar
  • 2 teaspoons Pure vanilla extract
  • 1 teaspoon Ground cinnamon
  • 1/4 teaspoon Salt
  • 2 cups Blueberries Fresh or frozen (do not thaw)
  • Butter For greasing the baking dish
II. Streusel Crumb Topping (Optional)
  • 1/2 cup All-purpose flour
  • 1/2 cup Packed light brown sugar
  • 1/2 teaspoon Ground cinnamon
  • 1/4 cup Cold unsalted butter 4 tablespoons, cut into small cubes
III. Simple Glaze (Optional)
  • 1 cup Powdered sugar
  • 2 to 3 tablespoons Milk or heavy cream
  • 1/2 teaspoon Vanilla extract

Equipment

  • 9x13 Baking Dish
  • Large Mixing Bowl
  • Whisk
  • Pastry Blender (Optional)

Method
 

Step 1: Prepare the Casserole Dish and Bread
  1. Grease a 9x13 inch baking dish generously with butter. Arrange the bread cubes evenly in the prepared baking dish. Distribute the 2 cups of blueberries over the top of the bread cubes.
Step 2: Whisk the Custard Mixture
  1. In a large bowl, whisk together the 8 large eggs until frothy. Add the whole milk (or half-and-half), granulated sugar, vanilla extract, cinnamon, and salt. Whisk vigorously until the sugar has fully dissolved.
Step 3: Assemble and Soak (The Critical Overnight Step)
  1. Carefully pour the custard mixture evenly over the bread and blueberry mixture, ensuring every piece of bread is moistened. Press down gently on the bread with a spatula to help it absorb the liquid.
  2. Cover the baking dish tightly with plastic wrap or aluminum foil. Refrigerate and allow the casserole to soak for a minimum of 4 hours, but ideally overnight (8 to 12 hours).
Step 4: Prepare the Streusel Topping (If Using)
  1. In a medium bowl, whisk together the flour, light brown sugar, and cinnamon. Cut in the cold butter cubes using a pastry blender or your fingers until the mixture resembles coarse crumbs. Place the bowl in the refrigerator.
Step 5: Bake the Casserole
  1. Preheat your oven to 375°F (190°C). Remove the casserole from the refrigerator 30 minutes before baking to allow it to temper.
  2. If using the streusel topping, remove the plastic wrap and sprinkle the streusel evenly over the top. Cover the dish loosely with aluminum foil.
  3. Bake for 30 minutes covered. Remove the foil and continue baking for an additional 20 to 25 minutes, or until the casserole is golden brown, puffed up, and a knife inserted into the center comes out clean (internal temperature 185°F).
Step 6: Glaze and Serve (Optional)
  1. Allow the casserole to rest for 10-15 minutes after removing it from the oven.
  2. Prepare the glaze: Whisk the powdered sugar, milk (or cream), and vanilla extract until smooth. Drizzle the glaze over the warm casserole just before serving. Serve warm with maple syrup or extra fresh berries.

Notes

For the best texture, always use day-old bread, or lightly toast fresh bread cubes (350°F for 10 minutes) before assembling the casserole. This ensures the bread absorbs the custard without falling apart. The casserole can be kept covered in the refrigerator for up to 24 hours before baking.