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Blueberry French Toast Casserole

Overnight Blueberry French Toast Casserole

This easy, make-ahead breakfast casserole is perfect for holidays or brunch. Sturdy bread cubes are soaked overnight in a rich vanilla-cinnamon custard, layered with sweet blueberries, and baked until golden brown and irresistibly fluffy.
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Prep Time 15 minutes
Cook Time 50 minutes
Total Time 1 hour 5 minutes
Servings: 8 servings
Course: Breakfast, Brunch, Dessert
Cuisine: American
Calories: 380
Ingredients Equipment Method Notes

Ingredients
  

For the French Toast Base
  • 1 loaf (13 to 16 ounces) sturdy bread (such as Challah or Brioche), cut into 1-inch cubes (about 8 to 9 cups) Stale bread works best for maximum absorption.
  • 1 tablespoon unsalted butter, softened For greasing the pan.
  • 2 cups fresh or frozen blueberries Do not thaw if using frozen.
For the Custard Mixture
  • 8 large eggs
  • 2 cups whole milk Or half-and-half for a richer flavor.
  • 1/2 cup granulated sugar
  • 1/4 cup light brown sugar, packed
  • 1 tablespoon vanilla extract
  • 1 teaspoon ground cinnamon
  • 1/4 teaspoon ground nutmeg
  • 1/4 teaspoon salt
For Serving (Optional)
  • Powdered sugar For dusting.
  • Maple syrup For drizzling.

Equipment

  • 9x13 inch baking dish
  • Large Mixing Bowl
  • Whisk

Method
 

STEP 1: Prepare the Baking Dish and Bread
  1. Generously grease a 9x13 inch baking dish with the softened unsalted butter.
  2. Spread the cubed bread evenly across the bottom of the prepared baking dish. If the bread is very fresh, allow it to sit out for an hour or two to dry slightly, as stale bread absorbs the custard better.
  3. Sprinkle the 2 cups of blueberries evenly over the layer of bread cubes.
STEP 2: Whisk the Custard Mixture
  1. In a large mixing bowl, crack the 8 large eggs. Whisk them vigorously until the yolks and whites are fully combined and slightly frothy.
  2. Add the whole milk, granulated sugar, light brown sugar, vanilla extract, cinnamon, nutmeg, and salt.
  3. Whisk the mixture thoroughly until the sugars are completely dissolved and all the ingredients are well incorporated.
STEP 3 & 4: Assemble and Chill (Overnight)
  1. Carefully pour the custard mixture slowly and evenly over the bread and blueberries in the prepared baking dish. Ensure that all the bread cubes are saturated with the liquid.
  2. Gently press down on the bread cubes with a spatula or the back of a spoon to help them absorb the custard.
  3. Cover the baking dish tightly with plastic wrap. Refrigerate the casserole for a minimum of 4 hours, or ideally, overnight (up to 12 hours). This step is crucial for achieving a fluffy texture and preventing a soggy bottom.
STEP 5 & 6: Preheat and Bake
  1. The next morning, remove the casserole from the refrigerator. Preheat your oven to 375°F (190°C). Allow the casserole to sit on the counter and come close to room temperature for about 20 to 30 minutes while the oven preheats.
  2. Remove the plastic wrap from the baking dish. Place the casserole in the preheated oven on the center rack.
  3. Bake for 45 to 55 minutes. The casserole is done when it is golden brown, puffed slightly, and the center is set (a knife inserted into the center should come out clean of wet custard).
STEP 7: Cool and Serve
  1. Remove the French toast casserole from the oven and allow it to cool slightly for 10 to 15 minutes before serving. This allows the internal structure to stabilize.
  2. Dust generously with powdered sugar and serve warm with a drizzle of maple syrup, if desired.

Notes

If you are short on time, you can bake this immediately after assembly, but you must still soak it for at least 30 minutes to an hour for the bread to absorb some liquid. For a crunchy topping, mix 1/4 cup melted butter, 1/4 cup brown sugar, and 1/2 teaspoon cinnamon, and sprinkle it over the casserole right before baking.