Easy overnight breakfast casserole with sausage, eggs, and cheese. No-soggy, make-ahead, freezer-friendly brunch bake for holidays or meal prep.

Meet your new brunch MVP: a foolproof breakfast casserole that’s savory, cozy, and wildly flexible. This easy breakfast casserole layers toasty bread or hash browns with sausage, fluffy eggs, and melty cheese for a crowd-pleasing bake that works for Christmas morning, weekend brunch, or meal prep. It’s the kind of overnight breakfast casserole that never fails at potlucks and makes hosting a breeze. Ready to see what makes this version extra good and how to tailor it for gluten-free, dairy-free, vegetarian, or high-protein needs?

What Makes This Breakfast Casserole Special?

Why this one wins: I tested all the usual suspects—bread vs. hash browns, cream vs. milk, rest times, and baking temps—so you get a no-soggy, golden-topped brunch casserole every time.

No-soggy guarantee: Smart ratios and a quick toast of the base keep the center custardy and the edges crisp.
Overnight or same-day friendly: Assemble up to 24 hours ahead (or bake right away) for a true make-ahead breakfast casserole.
Hash browns or bread: Choose a classic sausage egg cheese casserole with cubed bread, or go full hashbrown breakfast casserole.
Freezer-tested: Freeze unbaked or baked slices for grab-and-go meal prep breakfast.
Flavor-forward: Garlic, onion, and a hint of Dijon make this far from basic.
Diet-friendly options: Gluten-free, dairy-free, and vegetarian swaps that keep texture on point.
Scales like a champ: Works in 8×8, 9×13, or two pans for an easy Christmas breakfast casserole.
Temperature you can trust: Pull at 165°F/74°C in the center for set-but-tender eggs.

Ingredient Notes

Build bold flavor from the start: here’s how to pick the best ingredients for an easy brunch casserole that tastes like you fussed.

Bread choice: Day-old French bread, sourdough, brioche, or croissants give structure and richness; go GF with sturdy gluten-free loaves.
Hash browns: Shredded or diced, thawed and patted dry; go for plain, not seasoned, so you control the salt.
Sausage: Mild, hot, turkey, or chicken sausage all work; crumble finely for even bites.
Eggs: The backbone of the custard; room temp eggs whisk smoother and bake more evenly.
Milk + cream: Whole milk plus a splash of cream = tender set without greasiness; dairy-free milk works with a tablespoon of olive oil.
Cheese: Sharp cheddar for classic vibes; mix in Monterey Jack, Gruyère, or pepper jack for melt and flavor.
Veggies: Bell peppers, onions, spinach, and mushrooms add color and nutrition; sauté to drive off moisture.
Aromatics: Garlic and green onions add depth without overpowering the eggs.
Seasoning: Dijon, salt, black pepper, paprika, and a pinch of nutmeg make the custard sing.
Fresh finish: Chives, parsley, or salsa for serving keeps everything bright.

How To Make Breakfast Casserole

Here’s the game plan: simple steps, big payoff. This is the easy breakfast bake you’ll memorize after one go.

Prep the pan: Grease a 9×13-inch baking dish and heat the oven to 350°F/175°C. If baking later, line with parchment for easy lifting.
Toast the base: Lightly toast cubed bread on a sheet pan for 8 to 10 minutes, or par-bake thawed hash browns for 15 minutes. This prevents sogginess.
Cook the sausage: Brown sausage over medium heat, breaking into small crumbles. Drain excess fat so the casserole isn’t greasy.
Sauté the veg: In the same pan, cook onion and peppers with a pinch of salt until tender; add garlic for the last 30 seconds.
Whisk the custard: In a large bowl, whisk eggs, milk, cream, Dijon, salt, pepper, and paprika until smooth and airy.
Layer the base: Add toasted bread or hash browns to the dish. Scatter sausage and sautéed veggies over top.
Add the cheese: Sprinkle most of the cheese between layers for even melt; save some for the top.
Pour and rest: Pour the custard evenly over everything. Press lightly so all cubes get a soak. Rest 10 minutes (or cover and chill up to 24 hours).
Bake to perfection: Top with remaining cheese and bake 40 to 50 minutes, until golden and the center reads 165°F/74°C and only a slight jiggle remains.
Cool and slice: Rest 10 minutes so it sets cleanly. Garnish with chives and serve with fruit or a simple salad.

Pro Tips

Prevent sogginess: Toast the base, sauté veg to remove moisture, and avoid overloading with dairy.
Salt smart: Sausage and cheese are salty; season the custard lightly, then adjust at the table.
Make it overnight: Chill tightly covered 8 to 24 hours; add 5 to 10 minutes to bake time if very cold.
Crispy top: Broil 1 to 2 minutes at the end if you love extra browned cheese.
Internal temp: Pull at 165°F/74°C for custardy, not dry, eggs.
Crowd-size math: For 8×8, halve the recipe and bake 28 to 35 minutes; for two 9×13 pans, double and rotate halfway.

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Storage & Reheating

Make mornings effortless: this brunch casserole is tailor-made for prep, freezing, and quick reheat.

Refrigerate: Cover leftovers and chill up to 4 days.
Freeze baked: Cool, slice, wrap tightly, and freeze up to 2 months.
Freeze unbaked: Assemble in a freezer-safe dish, wrap well, freeze up to 2 months, thaw overnight before baking.
Reheat slices: Microwave 45 to 60 seconds or bake at 325°F/163°C for 10 to 12 minutes.
Reheat whole: Cover with foil and warm at 325°F/163°C for 20 to 30 minutes.
Meal prep: Portion into containers with fruit or greens for grab-and-go breakfast.

Variations & Substitutions

Customize the vibes: turn this into your signature overnight breakfast bake with these swaps and flavor spins.

Gluten-free: Use gluten-free bread or hash browns and confirm sausage is GF.
Dairy-free: Use unsweetened almond or oat milk plus 1 tablespoon olive oil; swap cheese for a melty DF alternative.
Vegetarian: Skip sausage and add sautéed mushrooms, spinach, and sun-dried tomatoes; a sprinkle of feta is great.
Mediterranean: Spinach, olives, roasted red peppers, oregano, and feta or mozzarella.
Southwest: Pepper jack, green chiles, corn, black beans, and a dash of cumin; top with salsa and avocado.
Everything bagel: Use bagel cubes, add caramelized onions, and sprinkle everything seasoning on top.
Hash brown base: Press thawed, dried hash browns into the pan with a drizzle of butter; par-bake for a crispy crust.
Croissant or brioche: For a richer Christmas morning breakfast casserole, use buttery croissant chunks.
High-protein: Add extra egg whites and swap turkey sausage; keep the cheese modest.
Lower-calorie: Use 2% milk, lean protein, and pile on veggies.
Kid-friendly: Mild sausage, sweet bell peppers, and cheddar keep it classic.

This easy breakfast casserole gives you brunch-hero energy with minimal effort. It’s savory, make-ahead, freezer-friendly, and endlessly customizable—from sausage egg cheese casserole to a veggie-loaded dairy-free breakfast bake. If holiday entertaining had a cheat code, this is it.

FAQ

Can I assemble this overnight?

Short answer: yes. Cover and chill 8 to 24 hours, then bake cold from the fridge and add 5 to 10 extra minutes if needed.

Bread or hash browns—which is better?

For classic texture: use day-old bread. For diner vibes: use crispy hash browns. Both are great as long as you toast/par-bake first to avoid soggy middles.

How do I prevent a soggy casserole?

Three big moves: toast the base, sauté veggies to cook off moisture, and don’t drown it in dairy. Bake until the center hits 165°F/74°C.

Can I make this gluten-free or dairy-free?

Gluten-free: use GF bread or hash browns. Dairy-free: use unsweetened almond or oat milk plus a DF cheese or skip cheese and add extra veg for body.

What size pan and bake time should I use?

Standard: 9×13-inch pan, 40 to 50 minutes at 350°F/175°C. Half batch: 8×8-inch, 28 to 35 minutes. Always check for 165°F/74°C in the center.

Can I freeze it?

Baked: cool, slice, wrap, and freeze up to 2 months. Unbaked: assemble, wrap well, freeze, thaw overnight, and bake as directed.

Why is the center still jiggly?

No panic: if the temp is below 165°F/74°C, bake a bit longer and tent with foil if the top is browning too fast. Rest 10 minutes before slicing so it sets.

Can I skip the sausage?

Absolutely: try sautéed mushrooms, spinach, and peppers for a vegetarian brunch casserole. Add feta or extra cheddar for richness.

Want more brunch wins: peek around my kitchen for more ideas that play nice with this easy brunch casserole.