Christmas Breakfast Casserole Recipe for Dinner Tonight

My christmas breakfast casserole gets assembled the night before and goes into the oven while everyone opens gifts. It feeds ten without any morning scrambling — just pull it from the fridge, preheat, and bake. The egg custard soaks into the bread overnight and bakes into something between a savory bread pudding and a classic egg bake.

Why This Christmas Breakfast Casserole Works

Letting the bread absorb the egg custard overnight is what separates a good casserole from a great one. The bread becomes custardy and tender through the center while the top crisps up and browns in the oven.

Breakfast sausage brings the seasoning — the sage and black pepper already in the sausage does the heavy lifting. You do not need to add a long ingredient list to get deep, savory flavor.

Sharp cheddar melts into the custard layer and crisps on top during baking. That golden cheese crust on a Christmas breakfast casserole is worth every second of oven time.

Ingredients

• 1 lb (450g) breakfast sausage, cooked and crumbled
• 8 large eggs
• 2 cups (480ml) whole milk
• 1 cup (115g) shredded sharp cheddar cheese, divided
• 6 slices white sandwich bread, cut into 1-inch cubes
• 1 small yellow onion, diced
• 1 teaspoon mustard powder
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1 tablespoon unsalted butter, for greasing

What You Need for Christmas Breakfast Casserole

Breakfast sausage — the pre-seasoned pork sausage sold in a roll (like Jimmy Dean). Crumble it as it cooks. Hot or mild both work — I use mild for a crowd with kids. Chicken sausage substitutes well for a lighter version.

Eggs — eight large eggs for 10 servings gives you a firm, sliceable set custard. Fewer eggs and the casserole comes out wet. More eggs and it becomes rubbery.

Whole milk — the fat in whole milk emulsifies with the eggs into a smooth custard. Two percent milk works but the custard will be slightly less rich. Half & half makes it richer and sets firmer.

Sharp cheddar — sharp cheddar has enough flavor to come through after baking. Mild cheddar disappears into the custard. Gruyere or a smoked gouda substitution makes a more elevated version.

White sandwich bread — soft bread with some structure holds the custard without turning to mush overnight. Day-old bread works best — it is slightly drier and absorbs without getting soggy. Brioche or croissant pieces make a richer, more tender casserole.

Mustard powder — one teaspoon sharpens the egg flavor and makes the custard taste more complex. It is not detectable as mustard in the finished dish.

Yellow onion — cooked in the sausage drippings for sweetness and depth. Skip if cooking for picky eaters — the casserole is complete without it.

How to Make Christmas Breakfast Casserole

1. Preheat the oven to 350°F (175°C). Grease a 9×13 inch (23×33 cm) baking dish with butter.
2. Cook sausage in a skillet over medium heat, breaking it apart, until browned and cooked through, about 8 minutes. Drain excess fat.
3. Add diced onion to the skillet with the sausage drippings. Cook for 3 minutes until softened.
4. Arrange bread cubes in a single layer across the bottom of the greased baking dish.
5. Scatter the cooked sausage and onion evenly over the bread.
6. Sprinkle 3/4 cup of shredded cheddar over the sausage layer.
7. Whisk together eggs, milk, mustard powder, salt, and pepper in a large bowl until fully combined.
8. Pour the egg mixture evenly over the casserole. Press the bread down gently to absorb the custard.
9. Sprinkle the remaining 1/4 cup of cheddar on top.
10. Bake uncovered for 45 minutes until the center is set and the top is golden.
11. Rest for 10 minutes before slicing and serving.

Christmas Breakfast Casserole Variations

Overnight Christmas Breakfast Casserole

Assemble through Step 9, cover with plastic wrap, and refrigerate overnight — up to 12 hours. Pull from the fridge while the oven preheats. Add 10 minutes to the bake time since it starts cold. This is the version I use every Christmas morning.

Croissant Christmas Casserole

Replace the sandwich bread with 6 day-old croissants torn into large pieces. The croissant layers create pockets of buttery, flaky texture through the custard. Add an extra 5 minutes to the bake time — croissants hold more moisture and need a little longer to set.

Vegetarian Version

Skip the sausage and add 1 cup of diced bell peppers, 1 cup of baby spinach, and 1/2 cup of sliced mushrooms sauteed in butter. Season the vegetables with garlic powder and smoked paprika before layering. The casserole still feeds 10 and holds together without the meat.

Green Chile Christmas Breakfast Casserole

Add one 4-ounce (115g) can of diced green chiles to the egg mixture before pouring. Substitute pepper jack for the cheddar. The heat level is mild and builds slowly — good for those who want a southwestern edge to their Christmas morning.

Hash Brown Christmas Casserole

Replace the bread with 3 cups of frozen hash browns, thawed and squeezed dry. Layer them on the bottom in place of the bread cubes. The potato base gives you a firmer, denser casserole that holds together in clean slices.

Tips for the Best Christmas Breakfast Casserole

• I always make this casserole the night before Christmas. The overnight soak transforms the bread into custard — a same-day assembly works but the texture is noticeably different.
• Drain the cooked sausage thoroughly. Excess grease in the casserole makes the egg custard oily and the texture heavy.
• Press the bread cubes down into the egg mixture after pouring. This helps every piece absorb custard evenly rather than floating on top.
• Cover the baking dish with foil for the first 25 minutes, then uncover for the remaining 20 minutes. This prevents the top from over-browning before the center sets.
• Check the center by inserting a knife — it should come out clean with no wet egg on the blade. A slight jiggle in the center is fine; it firms up during resting.
• This christmas breakfast casserole reheats beautifully. Leftovers microwave in 90 seconds or reheat in a 325°F (165°C) oven for 15 minutes covered.

Make Ahead & Storage

Assemble the full casserole the night before, cover tightly with plastic wrap, and refrigerate for up to 12 hours. Remove from the fridge 20 minutes before baking and add 10 minutes to the total bake time. The overnight soak actually improves the texture — the bread becomes fully saturated and the custard sets more evenly.

Baked leftovers keep in the fridge for up to four days. Slice into individual portions and store in an airtight container. Reheat single slices in the microwave for 90 seconds or the full casserole in a 325°F (165°C) oven covered with foil for 20 minutes. To freeze, cool completely, slice, wrap individual pieces in foil, and freeze for up to 2 months. Thaw overnight in the fridge before reheating.

Common Questions

Can I make Christmas breakfast casserole the night before?

Yes — this is the recommended method. Assemble through the final cheese sprinkle, cover, and refrigerate overnight. Pull it from the fridge when you preheat the oven and add 10 minutes to the bake time. The overnight soak improves the texture significantly over same-day assembly.

How do I know when the breakfast casserole is done?

Insert a knife into the center of the casserole. It should come out clean with no wet egg on the blade. The top will be golden and puffed slightly. A small amount of jiggle in the very center is fine — it firms up during the 10-minute rest period.

Can I use frozen hash browns instead of bread?

Yes. Thaw and squeeze the hash browns completely dry before layering them in the bottom. Use the same quantity — about 3 cups. The potato base gives you a denser, more substantial casserole that holds together in clean slices. Bake the same time and temperature.

What kind of sausage works best in this casserole?

Breakfast sausage sold as a bulk roll (not links) works best because it crumbles evenly. Jimmy Dean, Bob Evans, or any store brand all work. Hot or mild is a personal choice — I use mild for crowds. Chicken sausage or turkey sausage substitutes at the same weight.

How long does Christmas breakfast casserole keep in the fridge?

Up to four days in an airtight container. The flavor actually deepens by day two. Slice into individual portions before storing so each piece reheats evenly. Do not leave the casserole at room temperature for more than 2 hours.

This christmas breakfast casserole is the reason Christmas morning runs smoothly at my house every year. Save this recipe and tap the link for the full guide at MillennialHawk.com.