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Blueberry French Toast Casserole

Overnight Blueberry French Toast Casserole

A quintessential make-ahead breakfast casserole featuring crusty bread soaked in a sweet, spiced custard and studded with fresh or frozen blueberries. Prepare it the night before for an easy, impressive weekend brunch or holiday treat.
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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: 450
Ingredients Equipment Method Notes

Ingredients
  

For the French Toast Base
  • 1 loaf (13 to 16 ounces) sturdy bread such as 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 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

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 & 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 2 cups of whole milk or half-and-half, 1/2 cup of granulated sugar, 1/4 cup of light brown sugar, 1 tablespoon of vanilla extract, 1 teaspoon of ground cinnamon, 1/4 teaspoon of ground nutmeg, and 1/4 teaspoon of salt.
  3. Whisk the mixture thoroughly until the sugars are completely dissolved and all the ingredients are well incorporated.
  4. 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.
  5. Gently press down on the bread cubes with a spatula or the back of a spoon to help them absorb the custard.
STEP 4 & 5: Chill and Preheat
  1. Cover the baking dish tightly with plastic wrap and refrigerate the casserole for a minimum of 4 hours, or ideally, overnight (up to 12 hours). Allowing the casserole to chill ensures the bread fully absorbs the liquid.
  2. The next morning, remove the casserole from the refrigerator while you preheat the oven to 375°F (190°C).
  3. Allow the casserole to sit on the counter and come close to room temperature for about 20 to 30 minutes while the oven preheats. This helps ensure even baking.
STEP 6 & 7: Bake and Serve
  1. Remove the plastic wrap from the baking dish. Place the casserole in the preheated 375°F (190°C) oven on the center rack.
  2. 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).
  3. 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.
  4. Dust generously with powdered sugar and serve warm with a drizzle of maple syrup, if desired.

Notes

If you don't have time to chill the casserole overnight, let it soak for at least 4 hours. The goal is maximum saturation of the bread. For an extra crunchy top, sprinkle 1/4 cup of chopped pecans or a simple streusel topping over the casserole before baking.