Tulo

Overnight Christmas Breakfast Casserole Recipe

A golden, puffed sausage and cheddar breakfast casserole in a white baking dish, sliced into squares and topped with sliced green onions, steam rising from a corner piece on a plate.
Photo by Jonathan Borba on Pexels

The bread cubes sit in the egg and milk mixture overnight, so by morning they've absorbed the custard evenly instead of drying out on top while the bottom stays soggy. That means the entire dish goes from fridge to oven with no last-minute whisking, chopping, or dishes while everyone else is opening presents.

Prep
20 min
Cook
55 min
Total
1 hr 15 min
Servings
10

Ingredients

Servings10
  • 10 cups white or French bread, cubed
  • 1 lb breakfast sausage, bulk
  • 2 cups cheddar cheese, shredded
  • 1 cup red and green bell pepper, diced
  • 8 large eggs large eggs
  • 2 cups whole milk
  • 1 tablespoon dijon mustard
  • 1 teaspoon salt
  • 1/2 teaspoon black pepper
  • 1/4 cup green onions, sliced (for topping)

Nutrition per serving

Calories
462
Protein
23g
Carbs
27g
Fat
29g

Based on the recipe as written, one serving. Recalculates if you swap an ingredient above. An estimate only, exact values depend on the specific ingredients used.

Need different units or a different yield? Try our Conversion Calculator →

Instructions

  1. 1Grease a 9x13-inch baking dish. Spread the cubed bread in an even layer across the bottom.
  2. 2In a large skillet over medium heat, cook the breakfast sausage, breaking it up with a spoon, until browned with no pink remaining, about 8-10 minutes. Drain off excess fat.
  3. 3Scatter the cooked sausage, diced bell pepper, and shredded cheddar evenly over the bread cubes.
  4. 4In a large bowl, whisk together the eggs, milk, dijon mustard, salt, and pepper until fully combined and no streaks of egg white remain.
  5. 5Pour the egg mixture evenly over the bread, sausage, and cheese, then press down gently on the bread with a spatula so the top layer soaks up liquid too.
  6. 6Cover tightly with plastic wrap or foil and refrigerate for at least 8 hours, or up to 24 hours.
  7. 7The next morning, remove the casserole from the fridge and let it sit at room temperature for 20-30 minutes while the oven preheats to 350°F (175°C).
  8. 8Bake uncovered for 50-55 minutes, until puffed, deep golden on top, and set in the center, a knife inserted in the middle should come out clean, not wet with egg.
  9. 9Let the casserole rest for 10 minutes before slicing. Top with sliced green onions and serve warm.

Tips & variations

  • Swap the bulk sausage for diced ham or cooked, crumbled bacon for a different flavor without changing the method.
  • Day-old bread or lightly stale baguette holds its shape better than fresh, soft bread, which can turn mushy once soaked overnight.
  • For a vegetarian version, skip the sausage and add 2 cups of sauteed mushrooms and a handful of wilted spinach instead.
  • Croissants or brioche cubed in place of white bread make a richer, slightly sweeter casserole that pairs well with maple syrup on the side.

Storage & reheating

Cover and refrigerate leftovers for up to 4 days. Reheat individual portions in the microwave for 60-90 seconds, or cover the whole dish with foil and warm in a 300°F (150°C) oven for 15-20 minutes. Baked casserole can also be frozen in an airtight container for up to 2 months; thaw overnight in the fridge before reheating.

Tips from the Tulo kitchen

  • If mornings are too rushed to plan 8 hours ahead, the casserole can be assembled, baked right away, and it still turns out well, just slightly less custardy than the overnight version.
  • Line the baking dish with parchment paper hanging over the edges before adding the bread, so leftovers can be lifted out in one piece for cleaner slicing.

FAQ

Can I assemble this Christmas breakfast casserole the night before?

Yes, that's the intended method. Assemble it fully, cover, and refrigerate for 8 to 24 hours, then bake straight from the fridge the next morning after a short rest at room temperature.

Can I freeze the casserole before baking it?

Yes. Assemble it in a freezer-safe dish, wrap tightly, and freeze for up to 1 month. Thaw it completely in the refrigerator overnight before baking as directed.

Why did my casserole turn out watery or soggy?

This usually means it wasn't baked long enough for the center to fully set, or too much milk was used relative to bread. Bake until a knife in the center comes out clean, not just until the top looks golden.

Can I use a different bread for this recipe?

Yes, French bread, sourdough, croissants, or brioche all work well cubed. Denser breads like sourdough hold their texture best; softer breads like fresh sandwich bread can turn mushy after an overnight soak.

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