I always thought I had the perfect breakfast casserole recipe—one I made a few times a year for special occasions. Then I tried this version, and I realized I’d been wrong all along. This truly is the BEST breakfast casserole I’ve ever made. It’s more of a traditional egg casserole loaded with eggs, savory sausage, colorful bell peppers, and melty cheddar cheese, all baked into one glorious dish. The best part? You can make it the night before, so it’s absolutely perfect for Christmas morning, Easter brunch, or any special event where you don’t want to be stuck in the kitchen while everyone else is celebrating.
What makes this recipe special
This breakfast casserole is a crowd-pleaser that serves 12 people and only takes a few minutes to throw together. The combination of eggs, sour cream, and milk creates a creamy, light, and fluffy texture that’s absolutely irresistible. Unlike casseroles that use bread or potatoes as a base, this one is egg-forward, making it a great lower-carb option that still feels incredibly satisfying.
The recipe is wonderfully adaptable—you can customize it with different cheeses like pepper jack or Swiss, add more vegetables like spinach or zucchini, or swap the sausage for bacon. It’s equally perfect for holiday gatherings and busy weekday mornings since you can prep it ahead and simply bake when you’re ready. Leftovers reheat beautifully in the microwave, making it an excellent meal prep option for grab-and-go breakfasts throughout the week.
“This casserole is a hit every single time I make it! It’s perfect for preparing ahead when hosting friends and family, and it’s equally satisfying as a grab-and-go option during the work week.” — Robin
How this recipe comes together
The process is remarkably simple and straightforward. You’ll start by whisking together your eggs with sour cream, milk, cheese, salt, and pepper—the base of your casserole. An electric mixer on low speed makes this step quick and ensures everything is smoothly combined.
While the egg mixture rests, you’ll brown the sausage in a large skillet, breaking it into small pieces as it cooks. After draining most of the grease, the sausage gets added to the egg mixture. Then you’ll use that same skillet (less cleanup!) to quickly sauté the bell peppers and green onions for just 2-3 minutes until they’re slightly softened but still have some bite. Everything gets stirred together and poured into a greased 9×13-inch pan.
The casserole bakes at 350°F for 35-50 minutes. You’re looking for set edges with a center that’s just barely jiggly—it will continue cooking as it cools. The result is a golden, puffy egg casserole that’s creamy inside with slightly crispy edges.
What you’ll need
Main ingredients:
- 2 pounds pork sausage — Breakfast sausage works best; choose your preferred spice level
- 12 large eggs — The star of this casserole
- 1 cup sour cream (240g) — Light or regular both work; this creates the creamy texture
- ¼ cup milk (60ml) — Helps make the eggs light and fluffy
- 2 cups shredded cheddar cheese (200g) — Sharp or mild cheddar both taste great
Vegetables:
- 4 green onions, chopped — Adds mild onion flavor and color
- ½ green bell pepper, diced — For sweetness and crunch
- ½ red bell pepper, diced — Adds beautiful color and slight sweetness
Seasonings:
- 1 teaspoon kosher salt — Essential for bringing out all the flavors
- ½ teaspoon ground black pepper — Adds subtle warmth
Equipment needed:
- 9×13-inch glass baking dish
- Large skillet
- Large mixing bowl
- Electric mixer (optional but helpful)
Step-by-step instructions
- Preheat and prep: Set your oven to 350°F. Spray a 9×13-inch baking pan generously with cooking spray to prevent sticking.
- Mix the egg base: In a large bowl, combine the eggs, sour cream, milk, shredded cheddar cheese, salt, and black pepper. Use an electric mixer on low speed to blend everything together just until combined. Don’t overmix—you want it smooth but not overworked. Set this bowl aside.
- Cook the sausage: Heat a large skillet over medium heat. Add the pork sausage and cook, breaking it into small pieces with a wooden spoon or meat chopper as it browns. Continue cooking until no pink remains and the sausage is fully cooked through, about 8-10 minutes. Drain most of the grease (leave just a little for flavor), then add the cooked sausage directly to the bowl with the egg mixture.
- Sauté the vegetables: In the same skillet you used for the sausage (no need to clean it), add the diced bell peppers and chopped green onions. Sauté over medium heat for 2-3 minutes until they’re slightly softened but still have a bit of crunch. You don’t want them mushy—just barely cooked.
- Combine everything: Add the sautéed vegetables to the bowl with the eggs and sausage. Stir everything together until all the ingredients are evenly distributed throughout the egg mixture.
- Bake: Pour the entire mixture into your prepared 9×13-inch pan, spreading it evenly. Place in the preheated oven and bake for 35-50 minutes. Start checking at 35 minutes—the casserole is done when the edges are fully set and golden, and the center is just barely jiggly. It will continue to cook and set as it cools, so don’t overbake it or the eggs will be rubbery.
- Cool and serve: Let the casserole rest for about 5-10 minutes before cutting and serving. This allows it to set up properly and makes cutting clean slices much easier.
Best ways to enjoy it
Cut this breakfast casserole into generous squares and serve hot from the oven. It’s delicious on its own but can be enhanced with classic breakfast accompaniments. Serve with buttered toast, fresh fruit salad, crispy hash browns, or biscuits for a complete brunch spread.
For a Southwestern flair, top individual servings with salsa, sour cream, sliced avocado, and fresh cilantro. Hot sauce on the side lets everyone customize their spice level.
This casserole pairs beautifully with other brunch favorites like cinnamon roll cake, apple coffee cake, or peach scones if you want to offer both sweet and savory options. For a complete holiday breakfast table, add broccoli cheese quiche or a Monte Cristo sandwich.
Coffee, fresh orange juice, and a fruit platter round out a perfect brunch menu. The casserole is substantial enough to be the main dish, with sides playing a supporting role.
Keeping leftovers fresh
Store leftover breakfast casserole in an airtight container or cover the pan tightly with plastic wrap or aluminum foil. Refrigerate for 3-4 days. The eggs will firm up slightly when cold but remain delicious.
To reheat, microwave individual portions for 60-90 seconds until warmed through. The microwave works wonderfully for this casserole and doesn’t dry it out thanks to the sour cream in the mixture. For larger portions, reheat in a 300°F oven covered with foil for about 20-30 minutes.
For freezing, you have two excellent options. You can freeze the unbaked casserole: prepare everything as directed, pour into your pan, cover tightly with plastic wrap and then aluminum foil, and freeze for 2-3 months. Thaw overnight in the refrigerator, let come to room temperature for 30 minutes, then bake according to recipe instructions.
Alternatively, bake the casserole completely, let it cool, cut into individual portions, wrap each piece separately, and freeze for up to 3 months. This creates perfect grab-and-go breakfast portions that can be microwaved straight from frozen. Some readers even bake the whole thing, cut it up, and freeze the pieces for easy weekday breakfasts.
Pro chef tips
Don’t overbake: Start checking your casserole at 35 minutes. One reader noted that 55 minutes was too long and recommended checking at 30 minutes. Every oven is different, so watch for set edges and a barely jiggly center. The casserole continues to cook as it cools, so slightly underdone is better than overdone.
Use an electric mixer: While you can whisk by hand, an electric mixer on low speed makes quick work of combining the eggs, sour cream, and milk into a smooth, homogeneous mixture with no lumps.
Don’t skip draining the sausage: Even if you drain most of the grease, leaving a little bit adds flavor. But too much grease will make your casserole oily and heavy. Drain it well but not bone-dry.
Room temperature before baking: If you make this the night before and refrigerate it, let it sit at room temperature for 20-30 minutes before baking. This helps it cook more evenly and reduces the chance of a cold center.
Cut into portions before freezing: Several readers mentioned cutting the baked casserole into individual servings before freezing. This makes grabbing a quick breakfast so much easier—just microwave one piece for a couple of minutes.
The center should jiggle slightly: When you take the casserole out of the oven, the very center should still have a slight jiggle. It’s not raw—it will set up as it cools. Baking until completely firm results in rubbery, overcooked eggs.
Recipe variations
Cheese swaps: Try pepper jack for a spicy kick, Swiss for a milder, nuttier flavor, or a Mexican cheese blend for Southwestern flair. Gouda or Gruyère make this feel more sophisticated for special occasions.
Meat alternatives: Replace the sausage with crumbled bacon, diced ham, or cooked ground turkey for different flavor profiles. One reader loves making it with bacon instead of sausage. You could also use turkey sausage for a lighter option.
Dairy-free version: Multiple readers have successfully made this with dairy-free ingredients. Use dairy-free sour cream, milk alternatives like oat or almond milk, and dairy-free cheese. One reader reported it’s “wonderful both ways!”
Extra vegetables: Add sautéed mushrooms, fresh spinach, diced zucchini, or diced tomatoes to boost nutrition and flavor. Spinach wilts down nicely and adds beautiful color.
Lower carb focus: This casserole is already relatively low in carbs compared to versions with bread or potatoes. One reader specifically chose this recipe for a lower-carb Christmas breakfast, and even their daughter who doesn’t like peppers loved it!
Muffin tin version: For individual portions, divide the mixture among greased muffin tins and reduce baking time to about 15-20 minutes. Perfect for meal prep or portion control.
Half the recipe: This easily halves for smaller families. Use an 8×8-inch or 9×9-inch pan and reduce baking time to 25-35 minutes.
Your questions answered
Can I make this the night before? Absolutely! This is one of the best things about this recipe. Prepare everything as directed up until baking. Cover the unbaked casserole tightly and store it in the refrigerator overnight or up to one day. In the morning, let it sit at room temperature for 20-30 minutes, then bake according to the recipe instructions. Many readers do this for Christmas morning and other special occasions.
Can I prepare individual servings for meal prep? Yes! Several readers mentioned making this as a weekly meal prep option. You can either bake it in muffin tins for individual servings from the start (reduce baking time to 15-20 minutes), or bake the full casserole, cut it into portions, and freeze individually wrapped pieces for easy grab-and-go breakfasts.
Why does my casserole take less time than 55 minutes? Ovens vary significantly in temperature accuracy. One reader noted that 55 minutes was too long and recommended checking at 30 minutes. Start checking at 35 minutes and watch for set edges with a barely jiggly center. The casserole continues to cook as it cools, so err on the side of slightly underdone rather than overbaked.
Can I omit the bell peppers? Absolutely. The recipe is very adaptable. You can leave out the peppers entirely, reduce the amount, or replace them with other vegetables like mushrooms or spinach. One reader’s daughter doesn’t care for peppers but still loved the casserole, so they likely don’t dominate the flavor.
How do I reheat this for a crowd? If you want to bake it the day before and serve it at an event, bake completely, let cool, cover tightly, and refrigerate. Reheat covered in a 300°F oven for about 30 minutes until warmed through. Some readers have tried par-baking (partially baking) the night before and finishing in the morning, though results may vary with this method.
Can I use light sour cream and milk? Yes! The recipe specifically notes that light or regular sour cream both work. For the milk, whole milk creates the richest texture, but 2% or even lower-fat milk will still work. The sour cream is really what makes it creamy, so the milk fat content is less critical.
How many people does this really serve? The recipe yields 12 servings, which works well for a brunch or holiday breakfast where people are eating multiple dishes. For a main course breakfast with just a side or two, it might serve 8-10 hungry adults. You can easily cut leftovers into portions and freeze them for later.
Print
The Best Breakfast Casserole
- Total Time: 65 minutes
- Yield: 12 servings
- Diet: Gluten-Free
Description
A creamy and flavorful breakfast casserole loaded with eggs, savory sausage, bell peppers, and melted cheddar cheese, perfect for special occasions.
Ingredients
- 2 pounds pork sausage
- 12 large eggs
- 1 cup sour cream (240g)
- ¼ cup milk (60ml)
- 2 cups shredded cheddar cheese (200g)
- 4 green onions, chopped
- ½ green bell pepper, diced
- ½ red bell pepper, diced
- 1 teaspoon kosher salt
- ½ teaspoon ground black pepper
Instructions
- Preheat your oven to 350°F. Spray a 9×13-inch baking pan with cooking spray.
- In a large mixing bowl, combine the eggs, sour cream, milk, shredded cheddar cheese, salt, and black pepper. Blend until combined.
- In a large skillet over medium heat, cook the pork sausage until browned, about 8-10 minutes. Drain excess grease and add the sausage to the egg mixture.
- In the same skillet, sauté the bell peppers and green onions for 2-3 minutes until slightly softened. Add them to the egg and sausage mixture and stir to combine.
- Pour the mixture into the prepared baking pan and spread evenly. Bake for 35-50 minutes, or until the edges are set and the center is slightly jiggly.
- Let the casserole rest for 5-10 minutes before cutting and serving.
Notes
Great for meal prepping and can be frozen either unbaked or cooked for convenient breakfasts.
- Prep Time: 15 minutes
- Cook Time: 50 minutes
- Category: Breakfast
- Method: Baking
- Cuisine: American