Overnight Sourdough French Toast Casserole

This sourdough French toast casserole is the kind of breakfast that makes a lazy weekend feel special, but it’s easy enough to pull off on a holiday morning without stress. You tear the bread, pour over a vanilla-brown sugar custard, and let it hang out in the fridge overnight.

By the time you wake up, the only thing left to do is sprinkle on a buttery streusel and slide it into the oven. What comes out is a golden, craggy-topped dish that’s crisp on the edges and soft as pudding in the center.

Why This Casserole Works

Sourdough bread stays pleasantly distinct after an overnight soak, so you get tender bits that hold their shape instead of a uniform mush. The faint tang of the loaf cuts through the sweetness in a way plain white bread never does.

I keep coming back to this one because it does not ask for any stovetop babysitting. You do the work the night before, and in the morning you just bake and scoop. Leftovers, if you have any, reheat well for a few days.

Ingredients

• 1 loaf sourdough bread (about 1 lb): day-old or slightly stale works best
• 8 large eggs
• 2 cups whole milk
• 1/2 cup heavy cream
• 1/2 cup packed light brown sugar: for the custard
• 2 tsp vanilla extract
• 1 tsp ground cinnamon
• pinch of salt
• 1/2 cup cold unsalted butter, cubed: for the streusel
• 1/2 cup packed light brown sugar: for the streusel
• 1/2 cup all-purpose flour

Variations / Substitutions

• Dairy-free: swap the milk and cream with oat milk and a splash of full-fat coconut milk; use a plant-based butter for the streusel.
• No sourdough: challah or brioche work, but the result will be softer and sweeter; cut the brown sugar in the custard to 1/3 cup.
• Add fruit: fold 1 cup of fresh blueberries or sliced peaches between the bread cubes before adding the custard.
• Boozy twist: stir a tablespoon of bourbon or dark rum into the custard for a deeper warmth.

For an even simpler morning, you might like the Overnight Cinnamon Roll Casserole.

How to Make Overnight Sourdough French Toast Casserole

Step 1: Tear and Arrange the Bread

Tear the sourdough loaf into rough 2-inch pieces and pile them into a buttered 9×13-inch baking dish. You want a mix of sizes so some bits soak up plenty of custard while others keep a little chew.

If your bread is very fresh, leave the torn pieces out on the counter for an hour to dry slightly. Day-old bread soaks up the custard more evenly and holds its structure better after baking.

Step 2: Pour the Custard and Soak

In a large bowl, whisk together the 8 eggs, 2 cups whole milk, 1/2 cup heavy cream, 1/2 cup brown sugar, 2 teaspoons vanilla, 1 teaspoon cinnamon, and a pinch of salt. Keep whisking until the sugar looks dissolved, about 1 minute.

Pour the custard evenly over the bread, then use a spatula or clean hands to gently press the bread down so every piece is coated. Cover the dish tightly with plastic wrap and refrigerate for at least 8 hours, up to overnight. The next morning, the bread will have puffed up and you will see little cinnamon specks across the top.

Step 3: Top and Bake

When you are ready to bake, preheat the oven to 350°F (180°C). In a small bowl, rub together the 1/2 cup flour, 1/2 cup brown sugar, and 1/2 cup cold butter cubes with your fingers until the mixture looks like coarse crumbs with a few pea-sized butter bits.

Uncover the casserole and scatter the streusel evenly over the surface. Bake on the middle rack for 40 to 45 minutes. The topping should be deeply golden and the custard set, with just a slight wobble in the center. If the streusel browns too fast, tent the dish loosely with foil for the last 10 minutes.

Step 4: Scoop and Serve

Let the casserole cool for 10 minutes right in the dish, then scoop generous spoonfuls onto plates while it is still warm. The crisp topping will crack as you dig in, and the custard underneath will be soft and rich.

Serve with a drizzle of maple syrup, a handful of fresh berries, or a light dusting of powdered sugar. It is best right away, when the contrast between the crunchy top and tender center is at its peak.

A Few Notes for the Best Casserole

• Use day-old sourdough when you can; fresh bread soaks up liquid too fast and can turn mushy.
• If you are short on time, you can soak the bread at room temperature for 2 hours, but the overnight rest gives a more even texture.
• The streusel is optional. Leave it off and bake uncovered for a softer, pudding-like casserole.
• A teaspoon of orange zest or a splash of bourbon in the custard adds a nice layer of flavor without extra work.

Storing Leftovers

• Refrigerate: cover the dish tightly and store in the fridge for up to 4 days.
• Reheating: warm individual portions in a 300°F (150°C) oven for 10 minutes, or microwave for 30 to 45 seconds until heated through.

What to Serve with Sourdough French Toast Casserole

Crispy bacon or breakfast sausage gives a salty crunch that balances the sweet, custardy casserole. A bowl of fresh fruit or lightly sweetened yogurt adds brightness and cuts through the richness. For a bigger spread, roasted potatoes work well because their crisp edges and salt follow the same idea.

Frequently Asked Questions

Can I use gluten-free sourdough?

Yes, you can, but gluten-free bread tends to be drier and more crumbly, so reduce the soak time to 4 hours and use a slightly smaller dish so the custard covers it fully.

Why did my casserole turn out soggy?

A soggy casserole almost always comes from using fresh, soft bread that soaks up liquid too quickly and loses its structure. Day-old sourdough is much better at absorbing the custard without turning to mush.

Can I double the recipe?

You can double it; use a deeper casserole dish or a large roasting pan. Increase the bake time by 10 to 15 minutes and check that the center is set before pulling it out.

Can I assemble and freeze it?

Assemble the casserole (without the streusel) and freeze it before the overnight soak. When you are ready to use it, thaw overnight in the fridge, then add the streusel and bake as directed.

Sourdough French Toast Casserole Recipe

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Prep Time 15 minutes mins

Cook Time 45 minutes mins

Total Time 1 hour hr

Servings: 8 servings

Calories: 560

Ingredients Method Notes

Ingredients

  

• 1 loaf sourdough bread (about 1 lb)
• 8 large eggs
• 2 cups whole milk
• 1/2 cup heavy cream
• 1/2 cup packed light brown sugar
• 2 tsp vanilla extract
• 1 tsp ground cinnamon
• pinch of salt
• 1/2 cup cold unsalted butter, cubed
• 1/2 cup packed light brown sugar (for streusel)
• 1/2 cup all-purpose flour

Method

 

1. Tear the sourdough bread into 2-inch pieces and pile into a buttered 9×13-inch baking dish.
2. Whisk eggs, milk, cream, sugar, vanilla, cinnamon, and salt together. Pour over the bread, press down gently to coat, cover, and refrigerate at least 8 hours or overnight.
3. Preheat oven to 350°F (180°C). Rub flour, brown sugar, and butter together into a crumbly streusel. Uncover the casserole and scatter the topping evenly over it. Bake for 40 to 45 minutes until golden and set.
4. Cool 10 minutes, then scoop warm portions onto plates and serve with maple syrup or berries.

Notes

The hands-on time does not include the overnight soak, so plan ahead. If the streusel darkens too quickly in the oven, tent the dish loosely with foil for the last 10 minutes. Leftovers reheat well and keep for up to 4 days in the fridge.