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Blueberry French Toast Casserole

Overnight Blueberry French Toast Casserole with Streusel Topping

This rich, comforting breakfast bake requires essential overnight chilling to ensure the bread fully absorbs the sweet vanilla-cinnamon custard, yielding a perfect texture for brunch.
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Prep Time 15 minutes
Cook Time 55 minutes
Total Time 1 hour 10 minutes
Servings: 10 servings
Course: Breakfast, Brunch, Dessert
Cuisine: American
Calories: 420
Ingredients Equipment Method Notes

Ingredients
  

French Toast Base and Custard
  • 1 loaf French bread, Challah, or Brioche 13-16 ounce loaf, day-old, cut into 1-inch cubes
  • 8 large eggs
  • 2 cups whole milk Or half-and-half for extra richness
  • 1/2 cup granulated sugar
  • 2 teaspoons pure vanilla extract
  • 1 teaspoon ground cinnamon
  • 1/4 teaspoon salt
  • 2 cups fresh or frozen blueberries Do not thaw if using frozen
  • Butter for greasing the baking dish
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 cut into small cubes
Simple Glaze (Optional)
  • 1 cup powdered sugar
  • 2 to 3 tablespoons milk or heavy cream
  • 1/2 teaspoon vanilla extract

Equipment

  • 9x13 inch baking dish
  • Large mixing bowl
  • Whisk

Method
 

Prep and Soak (The Critical Step)
  1. Prepare the Casserole Dish and Bread: Generously grease a 9x13 inch baking dish with butter. Arrange the cubed bread evenly in the dish. Evenly distribute the 2 cups of blueberries over the top of the bread cubes.
  2. Whisk the Custard Mixture: In a large bowl, whisk the eggs until frothy. Add the milk, granulated sugar, vanilla extract, cinnamon, and salt. Whisk vigorously until the mixture is fully combined and the sugar has dissolved.
  3. Assemble and Soak: Carefully pour the custard mixture evenly over the bread and blueberries. Press down gently on the bread with a spatula to help absorption. Cover the dish tightly and refrigerate for a minimum of 4 hours, but ideally overnight (8 to 12 hours).
Prepare the Streusel (If Using)
  1. Mix Streusel: In a medium bowl, combine the flour, 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 until ready to bake.
Bake the Casserole
  1. Preheat and Top: Preheat your oven to 375°F (190°C). Remove the casserole from the refrigerator 30 minutes before baking. Remove the plastic wrap and sprinkle the chilled streusel evenly over the top.
  2. Bake: Cover the dish loosely with aluminum foil. 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 of 185°F).
Glaze and Serve
  1. Rest: Allow the casserole to rest for 10-15 minutes after removing it from the oven before slicing.
  2. Glaze (Optional): While the casserole cools, 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

Using stale or toasted bread is key to a successful French Toast Casserole; the starchier texture better resists becoming soggy. If you do not have day-old bread, cut the fresh bread into cubes and spread them on a baking sheet; toast at 350°F for 10 minutes until slightly dry.