Blueberry French Toast Casserole That's Custardy in the Center and Crispy on Top
This is the French toast casserole that delivers a bronzed, craggy top, a custardy center studded with jammy blueberries, and caramelized edges. Mix it the night before or the morning of — the oven does the rest. Perfect for holiday brunch or a lazy Sunday.
Equipment
- 9x13-inch baking dish (glass or ceramic)
- Large Mixing Bowl
- Whisk
- Knife and Cutting Board
- Plastic wrap or lid
Ingredients
Bread and Fruit
- 1 loaf stale bread (challah or brioche, about 1 lb)
- 2 cups frozen blueberries
Custard
- 8 large eggs
- 1.5 cups whole milk
- 0.5 cup heavy cream
- 0.25 cup maple syrup (Grade A dark)
- 1 tbsp vanilla extract
- 1 lemon zest of lemon
Topping and Assembly
- 1 tbsp butter (for greasing dish)
- 2 tbsp Demerara sugar
- to taste flaky salt (for serving)
- powdered sugar (for serving)
- extra maple syrup (for serving)
Instructions
- Cut and dry the bread: Slice the loaf into 1-inch cubes. If your bread is already stale, you're golden. If it's fresh, spread the cubes on a baking sheet and toast at 300°F for 10 minutes. Let them cool completely.
- Butter the dish: Use a generous tablespoon of softened butter. Get into the corners. This adds flavor and prevents the casserole from sticking.
- Make the custard: In a large bowl, whisk together 8 eggs, 1½ cups whole milk, ½ cup heavy cream, ¼ cup maple syrup, 1 tbsp vanilla, and the zest of one lemon. Whisk until completely smooth — no streaks of egg white.
- Assemble: Layer half the bread cubes in the dish. Scatter half the frozen blueberries over the top. Repeat with the remaining bread and blueberries. Pour the custard evenly over the top. Press down gently with a spatula so every piece of bread gets wet.
- Soak (optional but ideal): Cover and refrigerate for 30 minutes or overnight. This lets the custard penetrate every nook of the bread. If baking right away, press the bread down a few times while it sits.
- Bake: Preheat oven to 350°F. Sprinkle 2 tablespoons of Demerara sugar over the top. Bake for 45-50 minutes, until puffed, golden, and set in the center. If the top is browning too quickly, tent with foil at the 35-minute mark.
- Rest: Let it sit for 10 full minutes before slicing. The custard needs to re-set for clean slices.
- Finish and serve: Dust with powdered sugar, sprinkle flaky salt, and serve with warm maple syrup on the side.
Notes
The bread must be stale or dried out — this prevents a soggy casserole. Frozen blueberries burst better than fresh, creating jammy pockets. For make-ahead: assemble up to 24 hours in advance, add Demerara sugar just before baking. Leftovers can be frozen for up to 3 months; reheat covered at 325°F for 20 minutes, then uncovered for 5 to re-crisp the top.