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Blueberry French Toast Casserole

Overnight Blueberry French Toast Casserole

A make-ahead, comforting breakfast casserole featuring cubed bread soaked in sweet vanilla custard and bursting with fresh blueberries. Perfect for stress-free holiday mornings or brunch gatherings.
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Prep Time 15 minutes
Cook Time 50 minutes
Total Time 1 hour 5 minutes
Servings: 8 servings
Course: Breakfast, Brunch
Cuisine: American
Calories: 475
Ingredients Equipment Method Notes

Ingredients
  

For the French Toast Base
  • 1 loaf (13 to 16 ounces) sturdy bread (Challah, Brioche, or French bread) cut into 1-inch cubes (about 8 to 9 cups)
  • 1 tablespoon unsalted butter softened, for greasing the pan
  • 2 cups blueberries fresh or frozen (do not thaw if 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

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. Sprinkle the 2 cups of blueberries evenly over the layer of bread cubes.
STEP 2 & 3: Whisk the Custard and Assemble
  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 milk, granulated sugar, brown sugar, vanilla extract, cinnamon, nutmeg, and salt. Whisk the mixture thoroughly until the sugars are completely dissolved and all ingredients are well incorporated.
  3. 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. Gently press down on the bread cubes with a spatula to help them absorb the custard.
STEP 4 & 5: Chill and Preheat
  1. Cover the baking dish tightly with plastic wrap. Refrigerate the casserole for a minimum of 4 hours, or ideally, overnight (up to 12 hours). Chilling ensures the bread fully absorbs the liquid, creating a light, fluffy finished product.
  2. The next morning, remove the casserole from the refrigerator. Preheat your oven to 375°F (190°C) and allow the casserole to sit on the counter for about 20 to 30 minutes to come close to room temperature while the oven preheats.
STEP 6 & 7: Bake and Serve
  1. Remove the plastic wrap and place the casserole in the preheated 375°F (190°C) oven on the center rack. 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 should come out clean of wet custard).
  2. Remove the casserole from the oven and allow it to cool slightly for 10 to 15 minutes before serving. Dust generously with powdered sugar and serve warm with a drizzle of maple syrup, if desired.

Notes

Using slightly stale or dry bread is key to preventing a soggy French toast casserole. If your bread is very fresh, cut it up the night before and let it air dry before mixing with the blueberries. For an extra crisp topping, sprinkle 2 tablespoons of granulated sugar mixed with 1/2 teaspoon of cinnamon over the casserole just before baking.