Hearty Breakfast Sausage Casserole

There's something almost magical about pulling a bubbling breakfast casserole from the oven on a weekend morning—the kind of dish that fills your kitchen with warmth before anyone's even fully awake. I discovered this recipe during a chaotic holiday when I was hosting my extended family and realized I couldn't possibly flip pancakes for twelve people at once. Instead, I assembled this sausage casserole the night before, and it became the hero of breakfast: golden, savory, and requiring nothing but a simple slice and serve. Now it's my go-to whenever I want to feed people without the stress of standing over the stove.

I'll never forget the morning my teenage neighbor came over before school and took one look at this casserole cooling on my counter, then asked if he could stay for breakfast instead of heading straight home. His mom had sent him over to borrow something, and thirty minutes later, he was on his second helping, telling me stories about trying to cook for himself in his dorm-bound future. That single moment reminded me why I love making food for people—it's not just about the eating, it's about creating a reason for everyone to slow down together.

Ingredients

• Breakfast sausage (1 pound): This is the flavor backbone of the whole dish—browning it properly releases all those savory, slightly spiced notes that make people ask for the recipe.
• Bread cubes (6 cups, day-old): Use day-old bread so it's slightly dried out and will soak up the egg mixture without turning into mush; fresh bread falls apart, stale bread becomes custardy and perfect.
• Eggs (8 large) and whole milk (2 cups): These create the custard that transforms the casserole from just bread and meat into something creamy and cohesive.
• Cheddar cheese (2 cups) and mozzarella (1/2 cup): Cheddar brings sharp flavor and color, while mozzarella adds stretch and helps everything bind together.
• Yellow onion and red bell pepper (optional): If you add them, they cook down and add sweetness and texture, but the casserole is equally delicious without them.
• Salt, pepper, mustard powder, and paprika: These seasonings are subtle enough to let the sausage shine but add enough depth that it doesn't taste one-dimensional.

Instructions

Prep your dish and preheat:

Get your 9x13-inch baking dish greased and your oven to 350°F so everything's ready when you need it.

Brown the sausage:

In a large skillet over medium heat, break up the sausage with a spoon and cook it until it's no longer pink and the edges are just starting to crisp, about 5–7 minutes. If you're using onion and bell pepper, add them now and sauté until soft. Drain off any excess fat so your casserole isn't greasy.

Layer the bread and sausage:

Spread your bread cubes in an even layer in the prepared baking dish, then top with the cooked sausage (and vegetables if you used them). Don't worry about perfectly even coverage—it'll all come together when you pour the custard.

Make the custard:

In a large bowl, whisk together the eggs, milk, salt, pepper, mustard powder, and paprika until everything's smooth and well combined. This is your secret weapon—it's what transforms everything into a unified, creamy dish.

Add the cheese and combine:

Stir in 1 1/2 cups of cheddar and all the mozzarella into your egg mixture, making sure the cheese is evenly distributed. The cheese will melt when it bakes, but distributing it now means every bite will have flavor.

Pour and soak:

Pour the egg and cheese mixture evenly over the bread and sausage, then gently press the bread down with the back of a spoon so it's mostly submerged and can soak up all that custard. Let it sit for a minute if you're not baking right away—the bread will start drinking in the liquid.

Top and cover:

Sprinkle the remaining cheddar cheese over the top, cover the dish tightly with foil, and slide it into the oven.

Bake in two stages:

Bake covered for 30 minutes so everything stays moist and the custard sets gently. Remove the foil and bake for another 15 minutes until the top is golden and the center is just set—it should jiggle ever so slightly if you give the pan a gentle shake, not liquid but not rock-solid.

Rest before serving:

Pull it from the oven and let it sit for 10 minutes, which lets everything settle and makes it much easier to slice cleanly and serve.

Save

The best moment I've had with this casserole was when my friend who usually cooks for everyone else asked me to make it for his birthday breakfast. Watching him relax and enjoy food someone else had made for him—no stress, no rushing—felt like I'd given him the real gift. A good casserole does that; it creates space for connection instead of chaos.

Make-Ahead Magic

The beauty of this casserole is that it actually improves when you assemble it the night before. The bread cubes have all night to drink in the egg mixture, so they become more tender and custard-like, and the flavors have time to meld together. Just cover your assembled casserole with foil and refrigerate it, then pop it straight into a 350°F oven in the morning, adding about 10 extra minutes to the bake time since you're starting cold. I've found that baking it from cold actually gives you a slightly better texture—less likely to overcook on top while the center is still setting.

Flavor Variations That Actually Work

This casserole is forgiving enough to welcome changes but structured enough that it won't fall apart. I've swapped cheddar for sharp Swiss cheese and it became something more sophisticated, almost brunch-restaurant quality. Pepper jack gives it a subtle heat that people don't expect at breakfast. If you want to add vegetables, sautéed mushrooms are quietly luxurious, and a generous handful of chopped spinach stirred in right before baking adds color and nutrition without changing the character of the dish.

• Try adding a tablespoon of Dijon mustard to the custard for subtle depth that plays beautifully with sausage.
• A pinch of smoked paprika instead of regular paprika gives it a campfire-breakfast vibe.
• Fresh herbs like dill or chives stirred into the egg mixture right before pouring add brightness that cuts through the richness.

What to Serve Alongside

This casserole is filling enough to be the star of breakfast, but it benefits from simple accompaniments that add brightness or temperature contrast. Fresh fruit—berries, melon, citrus—cuts through the richness. A crisp green salad with a lemony dressing, though unconventional for breakfast, somehow works. Salsa or a good hot sauce is the classic move, giving you heat and acidity that wakes up your palate between bites.

Save

This casserole has become my answer to almost every breakfast gathering—it's the dish I reach for when I want to feed people and actually get to sit down with them instead of standing at the stove. That's the real magic of a good recipe.

Recipe Q&A

→ Can I prepare this dish in advance?

Yes, assemble it the night before, cover, refrigerate, and bake the next morning. Add about 10 extra minutes if baking straight from the fridge.

→ What can I use instead of cheddar cheese?

Swiss or pepper jack cheeses are great alternatives that bring a different flavor profile to the dish.

→ How can I add more vegetables?

Try stirring in chopped spinach or sautéed mushrooms to incorporate more veggies and enhance the texture.

→ What’s the best way to cook the sausage?

Cook the sausage in a skillet over medium heat, breaking it up as it browns, until fully cooked, about 5 to 7 minutes.

→ Is there a way to make the bread cubes soak the egg mixture better?

Press the bread gently after pouring the egg mixture to help the cubes absorb the liquid evenly throughout the dish.

→ Can this dish be customized for dietary needs?

Yes, using gluten-free bread or alternative sausage options can help tailor it to specific dietary preferences.