Name: Sausage and Spinach Breakfast Egg Casserole Recipe
Prep time: 20 min
Cook time: 45 min
Total time: 1 h 5 min
Cuisine: American
Ingredients: 10 to 12 ounces sausage (casing removed); 2 cloves garlic (minced); 3 cups fresh spinach (90 g); 2 large bell peppers (diced); ½ medium yellow onion (diced); 12 large eggs; ½ cup milk (any) (120 g); ½ cup shredded cheese (any flavor; divided) (56 g); Olive oil (for sautéing); Salt and pepper (to taste)

There’s just something so comforting about waking up to a warm, savory breakfast like this Sausage and Spinach Breakfast Egg Casserole Recipe. It’s filling, packed with flavor, and the best part? You can prep it the night before and wake up to breakfast ready to go!

The image shows a close-up of a rectangular baked dish divided into square pieces with one piece being lifted by a silver spatula. The dish has about four visible layers: the bottom layer is light and slightly crusty, the second layer is a mix of red and green bits suggesting chopped peppers and spinach, the third layer is creamy white, likely cheese or eggs, and the top layer is a golden orange melted cheese with browned spots and scattered dark green leafy bits. The baking dish is transparent glass placed on a white marbled surface. photo taken with an iphone --ar 2:3 --v 7

Jump to:

Why You'll Love This Recipe
Ingredients & Why They Work
Make It Your Way
Step-by-Step: How I Make Sausage and Spinach Breakfast Egg Casserole Recipe
Top Tip
How to Serve Sausage and Spinach Breakfast Egg Casserole Recipe
Make Ahead and Storage
Frequently Asked Questions:
Final Thoughts
Sausage and Spinach Breakfast Egg Casserole Recipe

Why You'll Love This Recipe

I’ve made this sausage and spinach casserole more times than I can count, especially when hosting weekend brunches. It’s that kind of recipe where you feel like you’ve put in effort, but it’s actually so simple. Plus, the spinach gives it a fresh pop that keeps it from being too heavy.

Great make-ahead option: Prep it the night before and bake it when you’re ready—total game-changer for busy mornings.
Balanced flavors: The savory sausage pairs perfectly with tender spinach and sweet bell peppers for a well-rounded bite.
Customizable: Cheese, veggies, or spice levels—you can tweak it to fit whatever you have or prefer.
Feeds a crowd: It’s a generous casserole that’s ideal for family breakfasts or meal prepping for the week.

This image shows a white speckled plate holding a square piece of egg casserole with three visible layers: the top layer is golden and melted cheese mixed with bits of green spinach and red peppers, the middle layer is creamy and light yellow with visible spinach and small red vegetable pieces, and the bottom layer contains cooked pieces of light brown potatoes and some egg mixture. Next to the casserole on the plate are roasted potato chunks that are golden brown and crisp. A silver fork rests on the edge of the plate. The plate sits on a white marbled surface with a dark green cloth partly visible underneath. Photo taken with an iphone --ar 2:3 --v 7

Ingredients & Why They Work

Every ingredient in this Sausage and Spinach Breakfast Egg Casserole Recipe plays a role in making it both tasty and nutritious. The sausage brings that meaty richness, while the spinach and peppers add fresh flavors and color. Here’s a quick rundown on why each one matters:

Flat lay of raw ground sausage in a mound, two cloves of peeled garlic, a small white bowl of olive oil, a handful of fresh green spinach leaves, two large diced red and yellow bell peppers mixed together, half of a medium yellow onion diced, a dozen whole large brown eggs with clean uncracked shells, a small white bowl filled with fresh milk, a small white bowl containing shredded cheese, a white ceramic bowl with mixed salt and black peppercorns placed symmetrically, all ingredients arranged neatly in perfect balance and symmetry, placed on a clean white marble surface, soft natural light, photo taken with an iPhone, professional food photography style, fresh ingredients, white ceramic bowls, no bottles, no duplicates, no utensils, no packaging --ar 2:3 --v 7 --p m7354615311229779997

Sausage: Use your favorite kind—spicy or mild—and make sure to remove casing for easier cooking and mixing.
Olive oil: Helps sauté the veggies and add a subtle richness without overpowering the other flavors.
Garlic: A small punch of garlic amps up flavor and pairs beautifully with sausage and spinach.
Fresh spinach: Gives the casserole a vibrant taste and sneaks in greens effortlessly.
Bell peppers: Diced for sweetness and crunch, they balance the richness of eggs and sausage.
Yellow onion: Adds a mild bite and depth of flavor when sautéed.
Eggs: The star binding ingredient that holds everything together, creating that perfect baked custard texture.
Milk: Makes the egg mixture silky and light instead of rubbery.
Shredded cheese: Adds melty, cheesy goodness—mix and match your favorites like cheddar, mozzarella, or pepper jack.
Salt & pepper: Essential seasonings to bring out all those delicious flavors.

📝

Note: You'll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Make It Your Way

I love how this breakfast casserole is a total blank canvas. Sometimes I add mushrooms or swap bell peppers for cherry tomatoes. You can even swap out the spinach for kale or omit the meat to keep it vegetarian. The key is making it your own and not stressing about perfection.

Vegetarian version: I’ve swapped sausage for sautéed mushrooms and chickpeas—still hearty and delicious!
Spice it up: Add a dash of cayenne or chopped jalapeños if you like a little heat in your morning meal.
Cheese combos: Mixing cheeses like feta and sharp cheddar gives a great balance of tang and meltiness.
Make it gluten-free: This recipe naturally fits gluten-free diets just by using your favorite sausage—watch the labels!

Step-by-Step: How I Make Sausage and Spinach Breakfast Egg Casserole Recipe

Step 1: Brown the sausage and prep your pan

Start by preheating your oven to 375°F (191°C) if you want to bake right after assembling. Then, take 10 to 12 ounces of sausage (remove the casing!) and brown it in a large skillet over medium heat. This browning step adds incredible flavor and texture. Don’t rush—letting it caramelize just a bit makes all the difference. While that’s cooking, lightly spray your 7 x 11 or 9 x 13-inch casserole dish with non-stick spray so the casserole doesn’t stick.

Step 2: Sauté the veggies

Using the same skillet (you’ll have some sausage fat leftover, which is perfect), add a bit of olive oil if it looks dry. Toss in minced garlic, fresh spinach, diced bell peppers, and half a diced yellow onion. Sauté everything for about 6 to 7 minutes until the spinach wilts and the peppers soften. Season with salt and pepper near the end to enhance the natural sweetness of the veggies. This mix brings a tender, flavorful bed for your eggs and sausage.

Step 3: Mix and layer

Transfer the veggies to your casserole dish with the browned sausage and stir gently but thoroughly to distribute the flavors evenly. Then, in a medium bowl, whisk together 12 large eggs, ½ cup of milk, and ¼ cup of shredded cheese. Pour this egg mixture evenly over the sausage and veggies, making sure it seeps through all the nooks. Finally, sprinkle the remaining ¼ cup of cheese plus a little extra salt and pepper for a perfect savory crust as it bakes.

Step 4: Bake and serve

Pop the casserole into the oven and bake for about 45 minutes. You’ll know it’s done when the edges start to brown and the center is set but still slightly wobbly—it will firm up as it cools. Let it rest at least 15 minutes before slicing so it sets well and is easier to serve. Trust me, this step makes your slices look perfect at the table.

Top Tip

Making this Sausage and Spinach Breakfast Egg Casserole Recipe has taught me a few neat tricks that really elevate the final dish. These tips will keep it moist, flavorful, and beautiful every time.

Don’t overmix the eggs: Whisk just until combined to keep the texture light and custardy, not rubbery.
Sear the sausage well: Brown it slowly for that deep, complex flavor that makes this casserole sing.
Let it rest before cutting: Cooling for at least 15 minutes helps everything set, so the slices hold together nicely.
Choose a medium oven temperature: Baking at 375°F gives a golden top and ensures the eggs don’t dry out or cook unevenly.

How to Serve Sausage and Spinach Breakfast Egg Casserole Recipe

sausage spinach casserole - Serving Suggestion

Garnishes

I usually finish my slices with a sprinkle of chopped fresh parsley or chives for a fresh, bright pop of color. Sometimes a dollop of sour cream or some hot sauce on the side adds a nice creamy or spicy kick—depending on the crowd!

Side Dishes

This casserole pairs beautifully with simple sides like fresh fruit salad, crispy hash browns, or even toasted crusty bread to sop up every last bit.

Creative Ways to Present

For holiday brunches, I’ve baked this in mini muffin tins for cute individual bites that are perfect for a buffet. It’s a fun and elegant way to serve guests without the fuss of slicing and plating large portions.

Make Ahead and Storage

Storing Leftovers

Once cooled, I store leftovers tightly covered in the fridge for up to 5 days. It reheats well in the microwave or oven, making it great for quick breakfasts or snacks during the week.

Freezing

I often freeze this casserole unbaked, wrapped tightly with plastic and foil. When I’m ready, I thaw it overnight in the fridge, then bake as usual. This trick makes weekend entertaining or holiday breakfasts super stress-free.

Reheating

To keep it from drying out, I reheat individual slices in the microwave with a cover or pop them in a 350°F oven for about 10-15 minutes until warmed through. It tastes almost as good as fresh!

Frequently Asked Questions:

Can I make the Sausage and Spinach Breakfast Egg Casserole Recipe ahead of time?

Absolutely! You can assemble the casserole up to 24 hours ahead and keep it covered in the fridge. When you’re ready, just bake it fresh from the refrigerator—this makes mornings so much easier.

What type of cheese works best in this casserole?

I like a mix depending on mood: sharp cheddar adds a punch, mozzarella melts beautifully for gooeyness, and pepper jack gives a subtle spicy kick. Feel free to experiment to find your favorite combo!

Can I freeze this sausage and egg casserole?

Yes! You can freeze it either unbaked or fully baked. Just wrap it tightly and freeze for up to 2 months. When freezing unbaked, thaw overnight before baking; for baked leftovers, reheat gently to preserve texture.

How do I reheat leftover casserole without drying it out?

I reheat individual portions in the microwave covered loosely with a microwave-safe lid or a damp paper towel. Alternatively, placing slices in a 350°F oven wrapped in foil for 10-15 minutes works wonders to keep moisture locked in.

Final Thoughts

This Sausage and Spinach Breakfast Egg Casserole Recipe has become such a staple in my kitchen because it’s flexible, reliable, and downright delicious. Whether I’m feeding family on a lazy Sunday morning or prepping ahead for a busy week, it never disappoints. I hope you’ll give it a try and find it as comforting and easy as I do—just like sharing a warm breakfast with a good friend.