Name: Egg Bake Breakfast 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 (90g); 2 large bell peppers (diced); ½ medium yellow onion (diced); Salt and pepper (to taste); 12 large eggs; ½ cup milk (120g, any type); ½ cup shredded cheese (56g, any flavor; divided); Olive oil (for sautéing)

There’s something so comforting about this warm, savory dish that fills your kitchen with cozy morning vibes. I’m excited to share my Egg Bake Breakfast Casserole Recipe—it’s perfect for busy mornings, gatherings, or whenever you want a fuss-free hearty breakfast that feels homemade and special.

This image shows a clear glass baking dish filled with a baked egg casserole cut into square pieces. The casserole has three visible layers: the bottom layer is light yellow and smooth, the middle layer contains bits of green spinach and small red pieces of pepper, and the top layer is golden brown with melted cheese that looks bubbly and slightly crispy in places. A silver spatula lifts one square piece from the dish, showing its thick texture and the blend of colors inside. The background is 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 Egg Bake Breakfast Casserole Recipe
Top Tip
How to Serve Egg Bake Breakfast Casserole Recipe
Make Ahead and Storage
Frequently Asked Questions:
Final Thoughts
Egg Bake Breakfast Casserole Recipe

Why You'll Love This Recipe

This egg bake breakfast casserole recipe has quickly become my go-to for weekends and even hectic weekdays when I want something comforting and hands-off. It’s a true crowd-pleaser that’s flexible, flavorful, and downright reliable.

Make-ahead friendly: You can prep it the night before, so mornings are a breeze.
Customizable ingredients: Easily swap veggies or cheese to suit your family’s tastes or what’s in season.
Balanced flavors and textures: Sausage, fresh veggies, and melty cheese come together perfectly.
Great for feeding a crowd: It scales up nicely, making it perfect for brunches or holiday mornings.

A white plate holds a square piece of egg casserole with visible layers: a top layer of melted golden and orange cheese mixed with green spinach pieces, a middle creamy egg layer with small bits of red peppers and herbs, and a bottom light egg base. Behind the casserole, there are several chunks of roasted potatoes with brown crispy edges and a few purple potato pieces. A silver fork rests on the edge of the plate, reflecting light softly. The plate is placed on a dark green cloth, and the background is a white marbled texture. photo taken with an iphone --ar 2:3 --v 7

Ingredients & Why They Work

Every ingredient in this egg bake breakfast casserole recipe plays a role in balancing taste, texture, and nutrition. From the savory sausage to the fresh veggies and fluffy eggs, here's why these ingredients shine together—and a few tips to get the best out of each.

Flat lay of raw sausage meat removed from casing in a loose mound, two whole uncracked brown eggs, a small handful of fresh bright green spinach leaves, two large diced bell peppers with red and yellow pieces visible, half a medium yellow onion diced, two peeled garlic cloves, a small white ceramic bowl with golden olive oil, a small white ceramic bowl with white milk, a small white ceramic bowl with pale yellow shredded cheese, a small white ceramic bowl with coarse salt and whole black peppercorns, all arranged symmetrically 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: Provides a rich, savory base and meaty texture. I prefer to brown it myself to get extra flavor and a little crispness, even if it’s pre-cooked.
Olive oil: Helps sauté the veggies without overwhelming them, plus it brings a lovely fruitiness.
Garlic: Delivers subtle pungency that wakes up the dish with fresh aromatics.
Fresh spinach: Adds a tender green note and helps brighten the casserole's color and nutrition.
Bell peppers: Their sweetness and crunch balance the richness of the sausage and eggs.
Yellow onion: Adds a mellow sweetness after sautéing and layers of flavor.
Salt and pepper: Essential to bring out every ingredient’s best.
Eggs: The stars that bind everything together into that perfect creamy, custardy texture.
Milk: Helps lighten the eggs for a silkier bake—any kind works!
Shredded cheese: Sprinkle inside and on top to get melty pockets of gooey goodness and a savory punch.

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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 adaptable the Egg Bake Breakfast Casserole Recipe is. Over time, I've found that tweaking vegetables or cheeses to what I have on hand can completely change the vibe without making the process complicated—giving you creative freedom in your kitchen.

Variation: I sometimes swap the sausage for cooked, crumbled bacon or even a plant-based sausage for a vegetarian twist—and it always turns out delicious!
Vegetable swaps: Try mushrooms, zucchini, or cherry tomatoes instead of the peppers and spinach for new flavors and colors.
Cheese choices: Sharp cheddar, pepper jack, or mozzarella all bring something unique; personally, I’m partial to smoked gouda for a cozy, smoky taste.
Spice it up: Adding red pepper flakes or chopped jalapeño gives a lovely kick if you like a little heat.

Step-by-Step: How I Make Egg Bake Breakfast Casserole Recipe

Step 1: Brown the Sausage for Maximum Flavor

Start by preheating your oven to 375ºF (191ºC) if you’re baking immediately. Then, in a large skillet over medium heat, brown your sausage. Even if your sausage is pre-cooked, I always brown it a bit more to bring out that extra depth and texture. Use a spatula to break it up into small pieces and cook until nicely browned. Drain excess grease if needed, then distribute the sausage evenly in your greased casserole dish.

Step 2: Sauté Your Veggies ‘til Tender and Tasty

Using the same skillet, add a splash of olive oil if the pan is dry—though often the sausage leaves enough grease to skip this. Toss in minced garlic, fresh spinach, diced bell peppers, and onions. Sauté everything for about 6-7 minutes until veggies are tender and spinach has wilted beautifully. Season with salt and pepper during the last minute to bring the flavors alive. Then, combine these cooked veggies with the sausage in your casserole dish, stirring gently to distribute evenly.

Step 3: Whisk Together Eggs, Milk, and Cheese

In a medium bowl, whisk 12 large eggs with half a cup of milk (any kind you prefer) and a quarter cup of shredded cheese. This mixture is the glue that holds everything together, creating a fluffy, creamy texture after baking. Pour it evenly over your sausage and veggie mixture in the casserole dish.

Step 4: Top and Bake (Or Refrigerate for Later)

Sprinkle the remaining cheese on top, add a pinch more salt and pepper, then decide when to bake. You can pop it right in the oven for about 45 minutes until the edges turn golden and the casserole feels set. Or, cover and refrigerate for up to 24 hours—this makes busy mornings so much easier because all the prep work is done. Just remember to let it sit for at least 15 minutes after baking before slicing—it helps it firm up so it holds together beautifully.

Top Tip

I’ve made this casserole dozens of times and learned a few tricks to make sure it comes out perfectly every time. These small tips helped me avoid soggy parts and uneven cooking, and I’m excited to share them with you.

Don’t skip browning the sausage: It adds caramelized flavor and texture that really wakes up the dish.
Use room temperature eggs: They mix better with the milk and cheese, which helps the casserole cook evenly.
Let rest before cutting: This keeps slices intact and makes serving much cleaner.
Reheat gently: I warm leftovers in the microwave briefly to keep the texture soft and delicious without drying out.

How to Serve Egg Bake Breakfast Casserole Recipe

Garnishes

I love topping my slices with a sprinkle of fresh chopped herbs like parsley or chives—it adds a fresh, vibrant pop that contrasts beautifully with the rich eggs and sausage. A dollop of sour cream or a light drizzle of hot sauce also livens things up depending on your mood.

Side Dishes

For a full, satisfying breakfast (or brunch), I like pairing this casserole with fresh fruit like berries or melon slices and a simple green salad with vinaigrette if it’s a brunch gathering. If you’re craving something warm, some toasted English muffins or crusty bread work great to scoop up any cheesy bits.

Creative Ways to Present

One fun way I’ve served this at holiday brunches is in individual ramekins topped with a little extra cheese and herbs, making everyone’s plate feel extra special. For casual get-togethers, cutting the casserole into bite-sized squares turns it into a perfect finger food.

Make Ahead and Storage

Storing Leftovers

Leftovers store beautifully in an airtight container in the fridge for up to 5 days. I usually slice the casserole into portions and keep them stacked with parchment paper between to prevent sticking. It makes grabbing a ready-to-reheat breakfast so simple during busy mornings.

Freezing

I often freeze this casserole either before baking or after. If frozen unbaked, I wrap it tightly in plastic wrap and foil, then thaw overnight in the fridge before baking as usual. Freezing it baked works well too—just reheat in the oven and it tastes nearly as fresh.

Reheating

I warm individual servings in the microwave for about 60-90 seconds, depending on your microwave’s power. To avoid dryness, I recommend covering with a damp paper towel or microwave-safe lid. For larger portions, reheating in the oven at 350ºF (177ºC) wrapped in foil keeps the texture perfect without drying out.

Frequently Asked Questions:

Can I make this egg bake vegetarian?

Absolutely! Just skip the sausage and add more veggies or substitute with plant-based sausage or cooked mushrooms for depth.

How far in advance can I prepare the casserole?

You can prepare and refrigerate the casserole mix up to 24 hours before baking with no issues.

What kind of cheese works best?

I recommend any shredded cheese you love—cheddar, mozzarella, pepper jack, or smoked gouda all work great. Use a mix for more complex flavor if you like.

Can this casserole be frozen?

Yes! It freezes wonderfully either before or after baking. Just be sure to wrap it well and thaw it overnight before baking or reheating.

Final Thoughts

This Egg Bake Breakfast Casserole Recipe is truly one of those dishes I return to again and again. It’s comforting, easy to make ahead, and endlessly customizable, so it suits whatever feeling or ingredients you have on hand. I love sharing it with friends because it’s so forgiving and always a hit. Honestly, once you try it, I think you’ll find it becoming a staple in your breakfast rotation, too. Give it a go—you won’t regret it.