The ultimate morning comfort food is here! This Overnight Breakfast Casserole is a wholesome, satisfying dish packed with layers of crispy hash browns, savory sausage, colorful veggies, and fluffy eggs — all brought together with melted cheddar cheese. It’s a surefire way to start the day on a delicious note.
Ideal for holidays, family brunches, or lazy weekend mornings, this make-ahead casserole takes the stress out of breakfast prep. Just assemble the night before and pop it in the oven in the morning. It’s warm, hearty, and crowd-pleasing — plus, you can easily customize it with your favorite mix-ins like mushrooms, different cheeses, or turkey sausage!
Full Recipe:
Ingredients:
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1 (32-ounce) package frozen hash browns
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Cooking spray
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1 pound ground breakfast sausage
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1 red bell pepper, chopped
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1 yellow bell pepper, chopped
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1/2 onion, chopped
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2 cloves garlic, minced
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1 teaspoon dried oregano
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2 cups fresh spinach
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2 cups shredded cheddar cheese
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10 large eggs
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2 cups milk
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1 tablespoon Dijon mustard
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Salt and pepper, to taste
Directions:
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Lightly grease a 9×13-inch baking dish with cooking spray. Evenly spread the hash browns on the bottom.
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In a large skillet over medium heat, cook the sausage for 2 minutes.
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Add bell peppers, onion, garlic, and oregano. Cook until sausage is browned and vegetables are soft, about 5 minutes.
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Stir in spinach and cook until wilted, about 1 minute.
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Spread the sausage and vegetable mixture over the hash browns in the baking dish. Top with shredded cheddar cheese.
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In a medium bowl, whisk together eggs, milk, mustard, salt, and pepper.
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Pour egg mixture evenly over the casserole. Cover and refrigerate for at least 8 hours or overnight.
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When ready to bake, preheat oven to 325°F (165°C).
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Bake uncovered for 50–60 minutes, or until the center is set and a knife inserted comes out clean.
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Let rest for 10 minutes before slicing and serving.
Prep Time: 25 minutes | Cooking Time: 60 minutes | Total Time: 9 hours (including chill time)
Kcal: 390 kcal | Servings: 10 servings
The Comfort and Convenience of an Overnight Breakfast Casserole
There’s something undeniably comforting about waking up to a hot, hearty meal that’s already prepped and ready to bake. The Overnight Breakfast Casserole offers this convenience in the most delicious way possible. It’s a dish that combines the wholesomeness of breakfast staples like eggs, sausage, cheese, and vegetables with the ease of make-ahead preparation. Perfect for busy families, weekend brunches, or special holiday mornings, this dish is a go-to solution for anyone looking to feed a crowd without standing over a stove first thing in the morning.
This casserole is popular not just for its taste, but for the practicality it brings to the table. By assembling everything the night before, the stress of morning prep disappears. Simply slide the dish into the oven the next day, and within an hour, you’ve got a bubbly, golden-brown masterpiece ready to serve. It’s truly a recipe that feels like a gift to your future self.
Why It’s a Crowd Favorite
What makes this casserole universally loved is its perfect balance of textures and flavors. The base of shredded hash browns offers a soft, comforting layer, complemented by the savory richness of browned breakfast sausage and the earthy crunch of sautéed vegetables like bell peppers and onions. Fresh spinach adds color and nutrients, while shredded cheddar cheese melts into a gooey topping that ties everything together.
Eggs and milk form the custard that binds it all, giving the casserole a fluffy yet firm structure. A touch of Dijon mustard adds a subtle kick, enhancing flavor without overpowering the other ingredients. It’s this combination of hearty and fresh, savory and creamy, that makes each bite satisfying.
Moreover, the recipe’s flexible nature allows it to be adapted to suit all sorts of taste preferences and dietary needs. Whether you want to make it vegetarian, lower in fat, or spicier, it’s easy to customize without compromising the overall experience.
Ideal for Holidays and Special Occasions
The Overnight Breakfast Casserole shines during holidays like Christmas, Easter, or Thanksgiving weekend. While everyone else is unwrapping gifts or preparing for a family gathering, this dish is quietly baking in the oven, filling the house with the smell of sizzling sausage and melting cheese.
Since it can feed around 8 to 10 people, it’s ideal for larger groups. The ease of making it ahead means less time spent in the kitchen on the day-of, and more time spent enjoying moments with family and friends. Many hosts even prepare two pans — one for meat-eaters and one vegetarian — so everyone at the table can dig in.
Versatility in Ingredients and Flavors
One of the most appealing aspects of this breakfast casserole is how easily it can be modified. Not a fan of sausage? Swap in crispy bacon, diced ham, or turkey sausage. Want a vegetarian version? Skip the meat and add mushrooms, zucchini, or even roasted butternut squash.
You can also experiment with the cheese — sharp cheddar is classic, but Swiss, Monterey Jack, pepper jack, or feta can add new layers of flavor. The vegetable mix is endlessly customizable: red and green bell peppers, scallions, kale, or sun-dried tomatoes are all excellent additions.
Some people prefer a southwestern twist, adding diced jalapeños, black beans, and a sprinkle of cumin, then topping the casserole with avocado slices and salsa before serving. Others go for an Italian flair with mozzarella, basil, and crumbled Italian sausage.
The base can also be changed up. Instead of hash browns, try cubed day-old bread for a more traditional strata texture. Or use sweet potato hash for a slightly sweet, nutrient-rich twist. The flexibility of the recipe means you can use what you already have on hand and still come out with something delicious.
Storage, Leftovers, and Meal Prep
The Overnight Breakfast Casserole isn’t just good for special occasions — it’s also a meal prep superstar. Make a pan on Sunday and you’ll have breakfast ready for most of the week. The casserole stores beautifully in the fridge and reheats well in the microwave or oven.
Portion out slices into airtight containers for quick grab-and-go breakfasts, or freeze individual portions for later. To reheat from frozen, simply thaw overnight in the fridge and warm up in the oven at 300°F until heated through. It’s a lifesaver for busy mornings or when you’re hosting overnight guests.
Additionally, this dish can be scaled down or up depending on your needs. Halve the ingredients for a smaller family or double it for a large brunch buffet. Because it’s baked in one dish, cleanup is minimal — another perk for home cooks.
Nutritional Considerations and Healthy Twists
Although hearty and indulgent, the breakfast casserole doesn’t have to be heavy. There are several simple tweaks to make it healthier without sacrificing taste. Swap out full-fat cheese for reduced-fat varieties. Use turkey sausage or even vegetarian sausage crumbles in place of pork. Add more vegetables to increase fiber and nutrients.
You can also use egg whites or a mix of whole eggs and whites to reduce cholesterol and calories. Almond or oat milk can replace dairy milk for a lactose-free version. Even the hash browns can be replaced with riced cauliflower or other low-carb alternatives for keto-friendly eaters.
The dish also provides a great way to sneak in extra greens, especially for picky eaters. Chopped kale, chard, or even broccoli florets blend seamlessly into the egg mixture and offer an extra nutritional punch.
Tips for Perfect Execution
To ensure your casserole bakes evenly and turns out with the perfect consistency, follow these expert tips:
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Let the egg mixture soak thoroughly: Giving it a full overnight rest allows the flavors to meld and ensures the hash browns absorb the custard evenly.
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Use pre-cooked or drained meat: Any added protein should be fully cooked and as dry as possible before going into the casserole to prevent sogginess.
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Cover when refrigerating: Tightly seal the dish with plastic wrap or a lid while chilling to maintain moisture and prevent odors from the fridge.
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Rest before slicing: Once baked, allow the casserole to sit for 10–15 minutes before cutting. This helps it firm up and slice cleanly.
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Don’t skip seasoning: Since eggs and potatoes can be bland on their own, be generous with salt, pepper, and herbs to enhance the flavor.
Pairing and Serving Ideas
This casserole is incredibly satisfying on its own, but you can round out your brunch spread with a few simple sides. A light fruit salad, citrus wedges, or berry compote offer brightness and acidity to balance the richness of the dish. For something sweeter, pair it with cinnamon rolls, muffins, or banana bread.
On the savory side, roasted asparagus, sautéed mushrooms, or a fresh arugula salad make for elegant accompaniments. If you’re hosting guests, set up a coffee and mimosa bar alongside the casserole to create a cozy, elevated brunch experience.
For kids or casual mornings, serve it with ketchup, hot sauce, or salsa on the side. A dollop of sour cream or a spoonful of guacamole can also enhance the overall taste and texture.
Conclusion: A Must-Have for Every Home Cook
The Overnight Breakfast Casserole is more than just a recipe — it’s a solution to busy mornings, a gift to tired hosts, and a canvas for creativity. Whether you’re serving a family breakfast on a chilly weekend or hosting a lavish holiday brunch, this dish delivers comfort, flavor, and ease in every bite.
Its flexible nature means you’ll never get bored of it. It’s reliable, forgiving, and endlessly adaptable. With just a little prep the night before, you can start your day with a warm, satisfying meal that feels like it came from a cozy country kitchen — all without setting an early alarm. Every home cook should have this classic in their repertoire, ready to whip out for any occasion that calls for delicious food and stress-free mornings.