Holiday Breakfast Casserole: Make-Ahead Brunch for Christmas Morning.

There’s a particular kind of chaos that happens on holiday mornings—wrapping paper everywhere, people still in pajamas, coffee brewing, and everyone asking when breakfast will be ready. This holiday breakfast casserole is the solution I wish I’d discovered years earlier. You assemble it the night before, slide it into the oven when you wake up, and forty-five minutes later you have a hot, satisfying breakfast that feeds a crowd without requiring you to stand at the stove flipping eggs while everyone else opens presents.

I developed this recipe after too many holiday mornings spent scrambling eggs in batches, burning toast, and generally missing the fun while everyone else enjoyed themselves. A good breakfast casserole needs to be substantial enough to keep people satisfied through a long morning of festivities, flavorful enough that it feels special, and sturdy enough that it doesn’t turn into a soggy mess.

This version hits all those marks. Cubed bread soaks up a savory egg custard overnight, developing an almost French toast-like texture. Breakfast sausage adds protein and rich flavor, while cheese creates pockets of melted goodness throughout. Bell peppers and onions provide texture and a subtle sweetness that balances the richness. The result is something that tastes homemade and special without requiring culinary acrobatics at six in the morning.

What makes this breakfast casserole truly ideal for holidays is its flexibility. You can adjust it for dietary preferences, prepare it completely in advance, and serve it straight from the baking dish without any fancy plating. It’s the kind of recipe that lets you actually enjoy your holiday morning instead of spending it in the kitchen.

Ingredients

For the Casserole:

1 pound breakfast sausage (regular, sage, or spicy)
1 tablespoon butter for greasing
8 cups cubed day-old bread (about 1 pound), cut into 1-inch pieces
2 cups shredded sharp cheddar cheese, divided
1 medium onion, diced
1 red bell pepper, diced
1 green bell pepper, diced
8 large eggs
2.5 cups whole milk
1 teaspoon Dijon mustard
1 teaspoon salt
1/2 teaspoon black pepper
1/2 teaspoon garlic powder
1/4 teaspoon paprika
2 tablespoons fresh parsley, chopped (plus more for garnish)

Optional Add-ins:

1 cup sautéed mushrooms
1 cup fresh spinach, chopped
4 slices cooked bacon, crumbled
1/4 cup sun-dried tomatoes, chopped
Different cheese varieties (Gruyere, mozzarella, pepper jack)

Instructions

Start by preparing the sausage and vegetables, which form the flavor base of this casserole. Heat a large skillet over medium-high heat and add the breakfast sausage, breaking it into small pieces with a wooden spoon. Cook until browned and cooked through, about 8-10 minutes. Use a slotted spoon to transfer the cooked sausage to a plate lined with paper towels to drain excess grease.

In the same skillet, reduce heat to medium and add the diced onion and bell peppers. If the pan seems dry, add a small drizzle of oil. Sauté for 5-7 minutes until the vegetables are softened and the onion becomes translucent. The vegetables should still have some texture—they’ll continue cooking in the oven tomorrow. Transfer to the plate with the sausage and let everything cool while you prepare the bread.

Generously butter a 9×13-inch baking dish, making sure to get the corners and sides. This prevents sticking and makes cleanup much easier. Spread the cubed bread evenly across the bottom of the dish. If your bread is fresh rather than day-old, you can toast the cubes lightly in a 300°F oven for about 10 minutes to dry them out. Day-old bread absorbs the egg mixture better without becoming mushy.

Scatter the cooled sausage and vegetable mixture over the bread cubes. Sprinkle 1.5 cups of the shredded cheddar cheese over everything, reserving the remaining half cup for topping before baking. The cheese gets distributed throughout the casserole rather than just sitting on top.

In a large bowl, whisk together the eggs until well combined and slightly frothy. Add the milk, Dijon mustard, salt, pepper, garlic powder, and paprika. Whisk thoroughly until completely smooth—you don’t want any streaks of egg white or unmixed seasonings. The Dijon adds a subtle tang that enhances the other flavors without being identifiable.

Pour the egg mixture evenly over the bread, sausage, and cheese in the baking dish. Use a spatula to gently press down on the bread cubes, making sure they’re all submerged in the liquid. Some pieces will pop back up, which is fine, but most should be soaking in the custard. Sprinkle the chopped parsley over the top.

Cover the dish tightly with aluminum foil or plastic wrap and refrigerate for at least 4 hours, but preferably overnight. This resting period is crucial—it allows the bread to fully absorb the egg mixture, resulting in a cohesive casserole rather than separated layers.

On the morning you plan to serve the casserole, remove it from the refrigerator and let it sit at room temperature while you preheat the oven to 350°F. This takes about 20-30 minutes and allows the casserole to come to room temperature, which promotes even cooking.

Remove the covering and sprinkle the reserved half cup of cheese over the top. Bake uncovered for 45-55 minutes, until the center is set and no longer jiggly when you gently shake the dish. The top should be golden brown and the edges slightly crispy. A knife inserted in the center should come out mostly clean with just a bit of moisture.

Let the casserole rest for 10 minutes before cutting and serving. This allows the custard to set fully and makes portioning much easier. Garnish with additional fresh parsley for a pop of color.

Flavor & Texture Notes

This holiday breakfast casserole delivers layers of complementary textures and flavors in every bite. The bread develops a texture somewhere between French toast and bread pudding—soft and custardy in the center while the top pieces get golden and slightly crispy at the edges. These crispy bits provide textural contrast that keeps the dish interesting.

The breakfast sausage adds a savory, slightly peppery flavor that grounds the dish and makes it substantial. The cheese melts into pockets of creamy richness throughout, with the top layer creating a golden, slightly crispy crust. The bell peppers maintain some texture even after baking, providing little pops of sweetness and fresh flavor against the rich egg custard.

The overall flavor is comforting and familiar—like a deconstructed breakfast sandwich in casserole form. The egg custard is seasoned just enough to enhance without overwhelming, allowing the individual components to shine. The Dijon mustard adds a subtle complexity that makes people wonder what makes it taste so good without being able to identify the secret ingredient.

What makes this casserole special is how it manages to be rich and satisfying without feeling heavy. The vegetables lighten it slightly, and the bread provides substance without greasiness. It’s the kind of breakfast that keeps you satisfied through holiday activities without that overstuffed feeling.

Tips & Variations

Bread Selection: French bread, sourdough, challah, or Italian bread all work beautifully. Avoid soft sandwich bread, which becomes too mushy. Day-old bread is ideal because it’s drier and absorbs the custard better. If your bread is fresh, cube it and let it sit out overnight or toast it lightly before using.

Protein Swaps: Substitute the sausage with cooked bacon, diced ham, or crumbled chorizo for different flavor profiles. For a vegetarian version, omit the meat entirely and double the vegetables, or use plant-based sausage. Smoked salmon with dill and cream cheese creates an elegant variation.

Vegetable Options: Mushrooms, spinach, tomatoes, zucchini, or asparagus all work well. Just make sure to sauté watery vegetables first to remove excess moisture. Frozen spinach must be thawed and thoroughly squeezed dry before adding.

Cheese Choices: Sharp cheddar provides great flavor, but Gruyere adds sophistication, mozzarella makes it milder, and pepper jack brings heat. A blend of cheeses creates complexity. Avoid pre-shredded cheese if possible—it contains anti-caking agents that affect melting.

Make It Lighter: Use turkey sausage, reduce cheese to 1 cup total, and substitute half the milk with unsweetened almond milk. You can also use egg whites for half the eggs, though this affects the richness and texture.

Spice Level: Add diced jalapeños, red pepper flakes, or use spicy sausage for heat. A dash of hot sauce in the egg mixture distributes spice evenly throughout.

Storage & Make-Ahead

This breakfast casserole is designed for make-ahead convenience. Assemble it completely up to 24 hours before baking and store covered in the refrigerator. The longer soak time actually improves the texture, so don’t worry about making it too far in advance within that window.

Leftover casserole stores in the refrigerator for up to 4 days in an airtight container. Reheat individual portions in the microwave for 1-2 minutes, or reheat the entire dish covered with foil in a 325°F oven for about 20 minutes. The reheated casserole won’t have the same crispy edges as fresh, but it’s still delicious.

You can freeze this casserole either before or after baking. To freeze unbaked, assemble it in a disposable aluminum pan, cover tightly with plastic wrap and then foil, and freeze for up to 2 months. Thaw completely in the refrigerator overnight before baking as directed. Baked casserole can be frozen in portions for up to 3 months—thaw overnight and reheat.

For the easiest holiday morning, prep all your ingredients the day before but keep them separate. In the evening, it takes just 15 minutes to assemble everything and get it in the fridge.

Serving Suggestions

This hearty breakfast casserole is substantial enough to be the centerpiece of your holiday brunch. Serve it with lighter sides to balance the richness—a fresh fruit salad with berries and citrus, a simple green salad, or sliced tomatoes with fresh basil.

For a complete holiday spread, pair the casserole with some lighter breakfast options. Offer fresh pastries or muffins for those who prefer something sweet, and set out yogurt and granola for lighter eaters. Coffee, fresh orange juice, and perhaps mimosas or bloody marys complete the festive morning.

Serve the casserole directly from the baking dish for a casual, family-style presentation, or cut it into neat squares and plate individually for a more formal brunch. A small garnish of fresh herbs makes each plate look polished without extra effort.

This casserole is perfect for potlucks or breakfast gatherings because it travels well and can be reheated easily. Transport it in the baking dish wrapped in towels to maintain warmth, or reheat at your destination.

FAQ

Can I make this casserole without refrigerating overnight? While overnight soaking produces the best texture, you can bake it after just 2-3 hours if needed. The bread won’t absorb quite as much custard, so the texture will be slightly less cohesive. For best results with shorter soaking time, use drier, day-old bread and press down firmly on the bread cubes to submerge them.

Why is my casserole soggy in the middle? This usually means either too much liquid, not enough soaking time, or underbaking. Make sure you’re using day-old or toasted bread that can absorb liquid well. Bake until the center is set and a knife comes out clean. If the top is browning too quickly but the center isn’t done, cover with foil and continue baking.

Can I use different types of milk? Yes, but stick with full-fat options for the best texture and flavor. Half-and-half makes it richer, while 2% milk works but produces a slightly less creamy result. Non-dairy milks like almond or oat milk work for lactose-free diets, though the flavor will be slightly different.

How do I know when the casserole is done? The center should be set and not jiggly when you gently shake the pan. A knife inserted in the center should come out mostly clean. The internal temperature should reach 160°F. The edges will look slightly pulled away from the sides of the dish and the top will be golden brown.

Can I double this recipe? Absolutely. Use two 9×13-inch dishes rather than one larger dish for even cooking. Baking time remains about the same. This is perfect for feeding a large crowd or having leftovers for several days. You can also freeze one casserole for a future breakfast.

Holiday mornings should be about spending time with the people you love, not being stuck in the kitchen while everyone else has fun. This breakfast casserole gives you that gift of time while still serving something homemade and satisfying. Whether you’re hosting a crowd or just want to make your own holiday morning special, this recipe proves that impressive doesn’t have to mean complicated. Make it once, and it’ll likely become your new holiday tradition—the kind of recipe that people request year after year and that makes your house smell like home.