Make-Ahead Brunch Casserole

This is the casserole you assemble Saturday night and slide into the oven Sunday morning. Bread cubes soak overnight in a seasoned egg-and-milk custard, absorbing all those flavors while you sleep. By morning, it’s ready to bake.

Two cheeses (cheddar and Swiss) melt into the custard base and create pockets of gooey, stretchy cheese throughout. The dry mustard in the egg mixture is subtle but important: it sharpens the cheese flavor without making anything taste like mustard.

Green onions, bell pepper, diced tomatoes, and mushrooms layered between the bread and custard give every forkful something different. The bacon goes on top (not buried) so it crisps up during baking instead of steaming in the custard.

Let it rest 10 minutes after baking. The center firms up and the custard sets, making it sliceable instead of soupy.

Kitchen Tips

• Use day-old bread or lightly toast fresh bread cubes. Fresh, soft bread turns to mush after soaking overnight.
• Seed the tomatoes before dicing. Tomato seeds and their gel release too much liquid into the custard and can make the center soggy.
• Check the center with a knife at 50 minutes. It should come out clean, not wet. Every oven runs a little different.
• Cook the bacon until very crispy before crumbling. It will soften slightly during baking, so starting extra-crisp keeps it from going limp.

Variations

• Swap bacon for crumbled breakfast sausage or diced ham.
• Add a layer of sautéed spinach or kale for a more veggie-forward brunch.
• Use sourdough bread cubes instead of white bread for a tangier, more rustic flavor.