Picture a golden, puffed casserole emerging from the oven, cheese bubbling at the edges and the aroma of toasted bread, savory sausage, and sweet peppers filling the kitchen.
Imagine tender cubes of crusty sourdough nestled in a silky custard, flecked with paprika and chives, each bite rich, warm, and comforting—the kind of breakfast that makes chilly mornings feel cozy and unrushed.
This Cheesy Egg Breakfast Casserole matters to me because it turns simple ingredients into a crowd-pleasing hug on a plate, perfect for busy school days, brunch with friends, or make-ahead holiday mornings when you want ease without sacrificing flavor.
When my family had an early soccer tournament, I assembled this the night before; the next day, I baked it while we packed—hot, hearty slices were ready right as we walked out the door. It’s dependable, adaptable, and impressively simple.
Ready? Let’s cook!
Why You’ll Love It
- Delivers bold flavor with sausage, peppers, and melty cheeses
- Feeds a crowd with minimal prep and simple steps
- Assembles ahead; bake fresh for stress-free mornings
- Flexible swaps for meats, veggies, and cheeses
- Satisfying, custardy texture with golden, bubbly top
Ingredients
- 8 large eggs — room temp helps whisk smoothly (use fresh, rich-yolk eggs)
- 2 cups milk — whole or 2% (choose hormone-free if possible)
- 1 cup heavy cream — for a custardy texture (look for high butterfat)
- 6 cups bread cubes, 1-inch — day-old French or sourdough (stale holds up better)
- 1 lb breakfast sausage — casing removed (find quality sausage with real hardwood smoke)
- 1 cup onion, diced — yellow or sweet (pick firm, heavy onions)
- 1 cup bell pepper, diced — any color (choose crisp, glossy peppers)
- 2 cloves garlic, minced — fresh (avoid sprouted cloves)
- 2 cups cheddar cheese, shredded — sharp preferred (grate from a block for melt)
- 1 cup mozzarella cheese, shredded — low-moisture (grate fresh for stretch)
- 1 tsp kosher salt — Diamond Crystal if available (season evenly)
- 1/2 tsp black pepper, freshly ground — medium grind (use a pepper mill)
- 1/2 tsp sweet paprika — not smoked (bright color, gentle warmth)
- 1/2 tsp dry mustard powder — enhances cheese flavor (check freshness)
- 2 tbsp butter, melted — for drizzling (use real butter, not spread)
- 2 tbsp chives, chopped — optional garnish (snip just before serving)
- 1/4 tsp red pepper flakes — optional heat (crush slightly for bloom)
Step-by-Step Method
Preheat & Prep the Dish
Preheat oven to 350°F. Grease a 9×13-inch baking dish with butter to prevent sticking and promote browning.
Gather all equipment and ingredients. Cube day-old bread into 1-inch pieces for better structure. Shred cheeses and dice onion and bell pepper. Mince garlic. This mise en place speeds cooking and guarantees even layering later.
Brown the Sausage
Heat a skillet over medium. Add breakfast sausage, breaking it into bite-size crumbles. Cook until browned and no pink remains, 6–8 minutes. Drain excess fat if needed to avoid a greasy casserole.
Transfer sausage to a plate. Keep the flavorful fond in the pan to enrich the vegetables in the next step.
Sauté the Vegetables
Return the skillet to medium heat. Add a little oil if dry. Sauté diced onion and bell pepper until softened and lightly golden, 4–5 minutes.
Stir in minced garlic and cook 30 seconds until fragrant. Remove from heat. Season lightly with a pinch of salt to draw out moisture and boost flavor.
Whisk the Egg Custard
In a large bowl, whisk eggs, milk, and heavy cream until smooth. Add kosher salt, black pepper, paprika, and dry mustard powder.
Whisk to fully combine and aerate slightly. Make certain no streaks of egg remain. Taste the custard (optional, before eggs if you prefer) to check seasoning, adjusting salt and pepper if needed.
Butter & Layer the Bread
Add bread cubes to the prepared baking dish in an even layer. Drizzle melted butter over the bread and toss gently to coat.
This adds richness and helps edges crisp. Spread the cooked sausage over the bread. Scatter the sautéed vegetables evenly to distribute flavor in each bite.
Add Cheese in Layers
Sprinkle half of the shredded cheddar and half of the mozzarella evenly over the casserole. Reserve the remaining cheeses for the top. Layering cheese now helps it melt into the bread and sausage, creating a cohesive interior. Keep distribution even to avoid dense pockets or bare spots.
Pour the Custard Evenly
Pour the egg mixture slowly and evenly over the entire casserole. Press down gently with a spatula to help the bread absorb the custard. Ensure all pieces are moistened but not submerged. Let sit 2–3 minutes to soak. This step guarantees a tender, custardy texture without dry pockets.
Top & Season the Casserole
Scatter the remaining cheddar and mozzarella over the surface. Sprinkle red pepper flakes if using for a subtle kick. Smooth the top for even browning. Optionally, add a light extra grind of black pepper. Check edges to ensure no dry bread remains exposed before baking.
Bake Until Set
Place the casserole on the center rack and bake uncovered for 40–45 minutes. Look for puffed sides, a golden top, and a center that’s just set with a slight jiggle. If browning too quickly, tent loosely with foil in the last 10 minutes. Aim for about 165°F internal temperature.
Rest, Garnish & Serve
Remove from the oven and rest 10 minutes to set the custard and ease slicing. Sprinkle chopped chives over the top for freshness and color. Cut into squares with a sharp knife. Serve warm. Pair with a crisp salad or fruit. Refrigerate leftovers promptly and reheat gently to maintain texture.
Ingredient Swaps
- Meat: swap sausage with cooked bacon or diced ham; for vegetarian, use sautéed mushrooms, spinach, or plant-based sausage.
- Dairy: replace heavy cream with half-and-half or extra milk; use lactose-free milk/cream and cheeses if needed; cheddar/mozzarella can be swapped for Monterey Jack, pepper jack, Swiss, or Colby.
- Bread: use any sturdy day-old bread (Italian, brioche, whole wheat); gluten-free bread works well—toast lightly first.
- Eggs: for lighter custard, use 6 eggs + 1 cup egg whites; for richer, add 1–2 extra yolks.
- Flavor boosts: replace paprika with smoked paprika or chili powder; swap dry mustard with 1 tsp Dijon; add herbs (parsley, thyme) or green chiles.
- Budget/regional: use bulk breakfast sausage or ground pork seasoned with salt, pepper, sage; sub bell pepper with poblano or canned green chiles; onion with leeks or scallions.
You Must Know
- Doneness • If the center jiggles like loose custard when nudged, leave it in until the middle wobbles slightly but doesn’t slosh and reaches 165°F on an instant-read; this guarantees set eggs without dryness.
- Troubleshoot • When the top is browned at 25–30 minutes but the middle is pale and wet, tent loosely with foil and continue 10–15 minutes; the foil slows surface browning so heat penetrates to the core.
- Make-Ahead • For overnight assembly, pull the chilled casserole to the counter for 20–30 minutes, then add 5–10 minutes to the oven time; starting closer to room temp prevents a cold center.
- Scale • For 12 servings in a 9×13, increase ingredients by 1.5x and expect 55–65 minutes total; check at 45 minutes and use both a 165°F reading and a knife coming out with moist crumbs, not liquid.
- Flavor Boost • If you want more savory depth, add 1 teaspoon Worcestershire and 1/2 teaspoon smoked paprika to the custard and swap 1 cup cheddar for sharp white cheddar; you’ll get a smoky, tangy edge that reads even through the 2–2.5 cups cheese.
Serving Tips
- Serve with fresh fruit salad and a dollop of sour cream or salsa.
- Pair with crispy hash browns and a simple arugula-lemon side salad.
- Plate squares atop warm marinara for a savory brunch twist.
- Offer hot sauce, chive yogurt, and avocado slices as customizable toppings.
Storage & Make-Ahead
Refrigerate leftovers in an airtight container 3–4 days.
Reheat covered at 325°F until warmed through.
Assemble the night before, cover, and chill.
Bake next morning, adding 5–10 minutes.
This casserole freezes well: wrap tightly (whole or portions) up to 2–3 months.
Thaw overnight in the fridge before reheating.
Reheating
Reheat gently: Microwave covered portions 50% power, 60–90 seconds, rest briefly.
Oven at 325°F, covered, 15–20 minutes.
Stovetop: covered skillet on low with splash of water, 5–8 minutes, until warmed.
Christmas Brunch Tradition
When Christmas morning glows soft and golden, I slide this cheesy egg casserole into the oven and let the savory aroma gather everyone to the kitchen.
I set mugs beneath the kettle, cue a softly crackling playlist, and watch the windows blush with winter light.
This casserole waits patiently—assembled the night before—so I can breathe, unwrap, and be present while it bakes to a puffed, golden crown.
When it’s set and custardy, I slice generous squares and shepherd folks to the table.
- Warm maple-sweet clementines and crisp bacon alongside for contrast.
- Pour cocoa or spiced coffee; keep a pot warm for refills.
- Lay out hot sauce, chives, and paprika for a festive sprinkle.
- Plate on warm dishes so cheese stays silky and melty.
Final Thoughts
Ready to wake up to something delicious? Give this cheesy egg breakfast casserole a try as written, or tweak it with your favorite add-ins—bacon, spinach, or extra spice—to make it your own!
Frequently Asked Questions
Can I Scale This Recipe for a Smaller 8×8-Inch Pan?
Yes—you can. I’d scale everything to about half, use 8×8, and bake 30–35 minutes, until puffed and just set. If assembling overnight, add a few minutes. Let it rest, then slice into cozy, custardy squares.
How Do I Make It Gluten-Free Without Compromising Texture?
Use sturdy gluten-free sourdough or brioche cubes, lightly toasted. I whisk an extra egg, add 1 teaspoon xanthan gum, and let bread soak 15 minutes. Bake till just set; it’ll slice tender, custardy, and beautifully golden.
What’s the Best Way to Prevent a Soggy Bottom?
Toast sturdy bread cubes, don’t skimp on day-old dryness, and pre-bake the base 8–10 minutes. I’ll drain sausage well, cool fillings, pour custard evenly, and bake on a preheated sheet pan for crisp, cozy edges.
Can I Freeze Unbaked Casserole and Bake From Frozen?
Yes—you can freeze it unbaked. I wrap it snugly, freeze up to 2 months, then bake from frozen at 350°F, tented. I add 15–25 minutes, watching for golden edges, puffed center, and custardy set.
How Long Can Leftovers Sit Out Safely at Room Temperature?
No more than 2 hours at room temperature; after that, bacteria bloom. I’d tuck leftovers into the fridge promptly, snug in airtight containers, then reheat until steaming hot, 165°F, so your next cozy bite stays safe and satisfying.
Cheesy Egg Breakfast Casserole
Equipment
- 1 9×13 inch baking dish
- 1 large mixing bowl
- 1 medium mixing bowl
- 1 Whisk
- 1 Spatula
- 1 Skillet
- 1 Knife
- 1 Cutting board
- 1 measuring cup
- 4 Measuring spoons
- 1 aluminum foil sheet optional
Ingredients
- 8 large eggs
- 2 cup milk whole or 2%
- 1 cup heavy cream
- 6 cup bread cubes day-old, 1-inch (French or sourdough)
- 1 pound breakfast sausage casing removed
- 1 cup onion diced
- 1 cup bell pepper diced
- 2 clove garlic minced
- 2 cup cheddar cheese shredded
- 1 cup mozzarella cheese shredded
- 1 teaspoon salt kosher
- 1/2 teaspoon black pepper freshly ground
- 1/2 teaspoon paprika sweet
- 1/2 teaspoon dry mustard powder
- 2 tablespoon butter melted
- 2 tablespoon chives chopped (optional)
- 1/4 teaspoon red pepper flakes optional
Instructions
- Preheat the oven to 350°F and grease a 9×13-inch baking dish with butter.
- Brown the sausage in a skillet over medium heat, breaking it up until cooked through, then transfer to a plate.
- Sauté the onion and bell pepper in the same skillet until softened, then stir in garlic for 30 seconds and remove from heat.
- In a large bowl whisk eggs, milk, heavy cream, salt, pepper, paprika, and mustard powder until smooth.
- Add bread cubes to the greased baking dish and drizzle with melted butter.
- Scatter cooked sausage, sautéed vegetables, and half of the cheeses evenly over the bread.
- Pour the egg mixture evenly over the casserole, gently pressing down to soak the bread.
- Top with remaining cheeses and sprinkle red pepper flakes if using.
- Bake uncovered for 40–45 minutes until puffed, golden, and the center is just set.
- Let rest for 10 minutes, garnish with chives, slice, and serve.
Notes
