Overnight Sourdough French Toast Casserole with Brown Sugar Pecan Topping

Name: Overnight Sourdough French Toast Casserole with Brown Sugar Pecan Topping
Prep time: 26 min
Cook time: 55 min
Total time: 1 h 21 min
Yield: 8 servings
Cuisine: American
Ingredients: 1 tbsp (14 g) unsalted butter, softened, for greasing the dish; 1 lb (450 g) stale sourdough bread, crust left on, cut into 1-inch (2.5 cm) cubes (about 10 cups); should feel dry and firm; 8 large (400 g) large eggs, at room temperature; 2 cups (480 ml) whole milk, cold; 1 cup (240 ml) heavy cream, cold; ½ cup (100 g) light brown sugar, packed; 1 tbsp (15 ml) pure vanilla extract; 2 tsp (5 g) ground cinnamon; ¼ tsp (½ g) ground nutmeg (optional); ½ tsp (3 g) fine sea salt; 4 tbsp (57 g) cold unsalted butter, cut into ½-inch (1 cm) cubes; ½ cup (100 g) light brown sugar, packed; ½ cup (60 g) all-purpose flour; 1 tsp (2½ g) ground cinnamon; ¼ tsp (1½ g) fine sea salt; ½ cup (55 g) pecans, coarsely chopped (optional); ½ cup (120 ml) pure maple syrup, warmed, for passing at the table

From the MyKitchenBank Kitchen

Cubes of stale sourdough soak overnight in a cinnamon-vanilla custard, then bake into a casserole with a custardy center, tender tangy bread, and a crisp brown sugar pecan crumble. It's an easy make-ahead brunch dish that puts leftover bread to good use.

Prep: 26 min
Cook: 55 min
Wait: 8 hr 40 min
Total: 10 hr 1 min
Makes: 1 (9×13-inch) casserole, 8 generous servings

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Ingredients

8 servings

For the casserole
1 tbsp (14 g) unsalted butter, softened, for greasing the dish
1 lb (450 g) stale sourdough bread, crust left on, cut into 1-inch (2.5 cm) cubes (about 10 cups); should feel dry and firm
8 large (400 g) large eggs, at room temperature
2 cups (480 ml) whole milk, cold
1 cup (240 ml) heavy cream, cold
½ cup (100 g) light brown sugar, packed
1 tbsp (15 ml) pure vanilla extract
2 tsp (5 g) ground cinnamon
¼ tsp (0.5 g) ground nutmeg (optional)
½ tsp (3 g) fine sea salt
For the topping
4 tbsp (57 g) cold unsalted butter, cut into ½-inch (1 cm) cubes
½ cup (100 g) light brown sugar, packed
½ cup (60 g) all-purpose flour
1 tsp (2.5 g) ground cinnamon
¼ tsp (1.5 g) fine sea salt
½ cup (55 g) pecans, coarsely chopped (optional)
To serve
½ cup (120 ml) pure maple syrup, warmed, for passing at the table

Equipment (8)

9×13-inch (23×33 cm) baking dish, at least 2 inches (5 cm) deep
Large bowl (5-quart / 4.7 L) for the custard and bread
Medium bowl for the topping
Whisk
Large rubber spatula
Aluminum foil
Instant-read thermometer
Serrated knife and cutting board

Steps

Before you start

Plan ahead: the casserole needs at least 8 hours (overnight) in the fridge for the best texture. If you're short on time, 2 hours is the minimum.
Your bread should be stale and dry (2–3 days old). If it's fresh, spread the cubes on a baking sheet and dry them in a 300°F (150°C) oven for 15–20 minutes, then cool completely before using.
Take the eggs out of the fridge and cut the topping butter into cubes, then return the butter to the fridge. It must stay cold for a crumbly topping.
Use a 9×13-inch (23×33 cm) baking dish at least 2 inches (5 cm) deep. A shallower dish may overflow.

1
Prep dish and bread
- Rub the 1 tbsp softened butter over the bottom and sides of a 9×13-inch (23×33 cm) baking dish.
- Using a serrated knife, cut the sourdough into 1-inch (2.5 cm) cubes, leaving the crust on.
- You should have about 10 cups.
- Scatter the cubes evenly in the dish.
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Ready when: Bread cubes are an even size and fill the dish in a loose, even layer.
Tip: If the bread feels soft in the center, dry it in a 300°F (150°C) oven for 15–20 minutes and cool it first, or the casserole will turn out soggy.
2
Whisk the custard
- In a large bowl, whisk the eggs until no streaks of white remain, about 1 minute.
- Add the milk, cream, ½ cup brown sugar, vanilla, 2 tsp cinnamon, nutmeg (if using), and ½ tsp salt.
- Whisk for 1–2 minutes until the sugar has dissolved and the mixture is uniform and pale tan, with no sugar grains on the bottom of the bowl.
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Ready when: Custard is smooth and the sugar is fully dissolved.
3
Soak the bread
- Pour the custard slowly and evenly over the bread cubes in the dish.
- Using a spatula, press the cubes down firmly so most of them are submerged, then gently turn the top cubes over.
- Repeat the pressing once or twice over the next few minutes, as the dry bread absorbs the custard.
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Ready when: Custard reaches about three-quarters of the way up the bread, and no dry patches remain on the top.
Tip: A few cubes poking above the custard is fine. They will crisp up nicely in the oven.
4
Make the crumble topping
- In a medium bowl, stir together ½ cup brown sugar, the flour, 1 tsp cinnamon, and ¼ tsp salt.
- Add the cold butter cubes and pinch them into the dry mixture with your fingertips until it looks like coarse, pebbly crumbs with some pea-sized clumps.
- Stir in the pecans, if using.
- Cover and refrigerate until baking.
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Ready when: Mixture forms coarse crumbs with no dry flour left in the bowl.
Tip: Work quickly so the butter stays cold. Melted butter makes a greasy, flat topping instead of a crisp one.
5
Chill overnight
- Cover the baking dish tightly with foil or plastic wrap and refrigerate for at least 8 hours and up to 18 hours (2 hours is the minimum if you're in a hurry).
- The bread will absorb nearly all of the custard.
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Ready when: Bread is plump and moist, with only a little custard pooled at the bottom of the dish.
6
Rest and preheatOven 350°F / 175°C
- Remove the casserole and the topping from the fridge.
- Let the casserole sit on the counter for 30 minutes while you preheat the oven to 350°F (175°C) with a rack in the center.
- Take off the cover once you're ready to bake.
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Ready when: Oven has reached 350°F (175°C) and the dish is no longer ice-cold to the touch.
Tip: Don't skip the rest. A fridge-cold casserole can take 15 minutes longer and cook unevenly.
7
Bake coveredOven 350°F / 175°C
- Cover the dish tightly with foil.
- Place it on the center rack at 350°F (175°C) and bake for 25 minutes.
- Covering it lets the custard begin to set without the tops of the bread scorching.
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Ready when: Casserole is puffed slightly and hot, and the edges look set.
Tip: Set a baking sheet on the rack below to catch any drips.
8
Add topping and uncoverOven 350°F / 175°C
- Remove the foil.
- Scatter the chilled crumble evenly over the top, all the way to the edges.
- Return the dish to the oven and bake, uncovered, 30 more minutes at 350°F (175°C).
- The casserole is done when the top is deep golden brown and the center no longer jiggles when you gently shake the dish.
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Ready when: Golden brown, crisp topping; center reads 160°F (71°C) on an instant-read thermometer, and a knife inserted in the center comes out clean with no raw egg.
Tip: If the topping is browning too quickly before the center is set, tent loosely with foil for the remaining time.
9
Rest before serving
- Transfer the dish to a wire rack and let it rest for 10 minutes.
- The custard will firm up so the squares hold their shape when cut.
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Ready when: Steam has slowed and the surface no longer looks wet or jiggly.
10
Warm syrup and serve
- Warm the maple syrup in a small microwave-safe cup for 20–30 seconds until hot to the touch (or gently in a small saucepan over low heat).
- Cut the casserole into 8 squares and serve warm, passing the syrup at the table.
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Ready when: Squares hold together with a soft, custardy center and crisp top.

Good to know

Tips

Use sturdy, dry bread. Soft sandwich-style sourdough breaks down and gets gummy, while crusty, chewy loaves keep their shape and give you pockets of custard.
Cut the cubes about the same size so they absorb the custard and bake at the same rate.
Check doneness with a thermometer: the center should reach 160°F (71°C). If it's under that, it will still be wet and eggy even if the top looks done.
Fresh berries, sautéed apples, or a handful of chocolate chips tossed with the bread in step 1 are great add-ins (up to 1½ cups / about 200 g).

Make ahead

"Assemble the soaked casserole (steps 1–3) up to 18 hours ahead and keep it tightly covered in the fridge. Keep the crumble topping in a separate covered container in the fridge for up to 2 days, and add it just before baking. Do not freeze the unbaked casserole, because the soaked bread turns mushy."

Storage & reheating

Room temperature: up to 2 hours after baking. Fridge: cover leftovers tightly and refrigerate up to 4 days. Freezer: wrap individual squares well and freeze up to 2 months; thaw overnight in the fridge. Reheat: place squares on a baking sheet and warm in a 325°F (160°C) oven for 12–15 minutes (20 minutes if frozen and thawed), or microwave a single square for 45–60 seconds, though the topping will soften.

Substitutions

pecans → chopped walnuts or sliced almonds. Use the same amount, or leave out for a nut-free casserole and add 2 tbsp (25 g) more flour and a pinch more cinnamon to keep the crumble full.
heavy cream → additional whole milk. Use 1 cup (240 ml) more whole milk. The result is a lighter, slightly less rich custard.
light brown sugar → pure maple syrup. Use ⅓ cup (80 ml) maple syrup in the custard in place of the sugar for a more pronounced maple flavor.
stale sourdough bread → stale brioche, challah, or French bread. Use the same weight. Enriched breads like brioche or challah soak faster, so 2–4 hours in the fridge is enough.