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blueberry french toast casserole in glass baking dish after baking

Unbelievable Blueberry French Toast Casserole

  • Author: Sally
  • Prep Time: 25 minutes
  • Cook Time: 50 minutes
  • Total Time: 1 hour, 15 minutes (plus overnight time)
  • Yield: serves 12
  • Category: Breakfast
  • Method: Baking
  • Cuisine: American


There’s not one word more perfect than “unbelievable” to describe this overnight blueberry French toast casserole. The casserole benefits from sitting in the refrigerator overnight before baking, so this is an excellent make-ahead brunch recipe!


  • 1 (12–14-ounce/340–400g) loaf French bread, sourdough bread, or challah*
  • 1 cup (140g) fresh or frozen blueberries*
  • 8 large eggs
  • 2 and 1/4 cups (540ml) whole milk
  • 1/2 teaspoon ground cinnamon
  • 3/4 cup (150g) packed light brown sugar
  • 1 Tablespoon (15ml) pure vanilla extract

Streusel Topping

  • 1/3 cup (69g) packed light or dark brown sugar
  • 1/3 cup (41g) all-purpose flour (spooned & leveled)
  • 1/2 teaspoon ground cinnamon
  • 6 Tablespoons (85g) unsalted butter, cold and cubed
  • optional: extra blueberries, maple syrup, and/or confectioners’ sugar for topping


  1. Grease a 9×13-inch pan with butter or nonstick spray. Slice, then cut the bread into cubes, about 1 inch in size. Spread cubes into the prepared baking pan and top evenly with blueberries. Set aside.
  2. Whisk the eggs, milk, cinnamon, brown sugar, and vanilla together until no brown sugar lumps remain. Pour over the bread. Cover the pan tightly and refrigerate for 3–24 hours. Overnight is best.
  3. Preheat oven to 350°F (177°C). Remove pan from the refrigerator.
  4. Prepare the topping: Whisk the brown sugar, flour, and cinnamon together in a medium bowl. Cut in the cubed butter with a pastry blender or two forks. Sprinkle the topping over the soaked bread.
  5. Bake for 45–55 minutes or until golden-brown on top. I usually bake it for 45 minutes because I like it softer.
  6. Serve warm. Cover leftovers tightly and store in the refrigerator for 2–3 days.


  1. Make Ahead & Freezing Instructions: Prepare the topping in advance, cover tightly, and store in the refrigerator. Sprinkle over the soaked bread before baking. For freezing, prepare the recipe through step 4 (without preheating the oven), and freeze for up to 2 months. Thaw overnight in the refrigerator, then bake as directed. Baked casserole can be frozen for up to 3 months. Thaw overnight in the refrigerator and warm up in a 350°F (177°C) oven for 35 minutes or until warm in the center.
  2. Special Tools (affiliate links): 9×13-Inch Baking Pan | Glass Mixing Bowls | Whisk
  3. Half Batch: This recipe can easily be halved in an 8-inch baking pan or 9-inch baking pan. The bake time will be slightly less, around 30–35 minutes.
  4. Bread: Day-old, crusty bread is perfect for French toast casseroles so it can soak up the egg custard. I typically use a loaf of challah bread that I slice and let sit out overnight. You’ll wind up with about 12 cups of cubed bread. A little more or less is OK. Here’s a shortcut for creating “stale” crusty bread: Spread the bread chunks on a lined baking sheet and toast in a 300°F (149°C) oven for 10 minutes.
  5. Fruit: Instead of blueberries, try strawberries, raspberries, or blackberries. In the fall, try cranberries or thinly sliced apples or pears. So many options!

Keywords: blueberry french toast casserole