Name: Homemade Southwest Breakfast Casserole
Prep time: 20 min
Cook time: 45 min
Total time: 1 h 5 min
Yield: 8
Cuisine: Southwest
Ingredients: 12 large eggs; 1 cup whole milk; 1 pound pork breakfast sausage; 4 cups frozen shredded hash browns; 1 cup shredded sharp cheddar cheese divided; 1 red bell pepper diced; 1 green bell pepper diced; 1 small yellow onion finely diced; 1 can 4 ounces diced green chiles drained; 1/2 cup sliced black olives; 1 teaspoon chili powder; 1 teaspoon ground cumin; 1 teaspoon kosher salt; 1/2 teaspoon black pepper; 2 tablespoons sliced green onions for garnish; Cooking spray or butter for greasing the pan

If your mornings feel rushed but you still crave a hearty, sit-down meal, this Homemade Southwest Breakfast Casserole is about to become your new favorite make-ahead breakfast. It’s loaded with savory sausage, fluffy eggs, melty cheese, and all the Tex‑Mex flavor you’d expect from your favorite breakfast burrito—just baked into one cozy pan.

I love this casserole for weekends when the house is full or on busy weekdays when I want to meal prep breakfasts in one go. You can assemble it the night before, bake it off in the morning, and watch everyone drift into the kitchen as the smell of smoky chili, cheese, and sausage fills the house.

What Makes This Homemade Southwest Breakfast Casserole So Irresistible?

For me, the magic of this casserole is all about layers of flavor and texture. Crispy browned breakfast sausage and sautéed peppers bring that classic Southwest vibe, while hash browns and sharp cheddar make it extra comforting and satisfying. Every bite has a little bit of everything—soft egg, gooey cheese, a pop of sweetness from bell peppers, and the briny punch of black olives.

It’s also incredibly forgiving. You can swap in your favorite proteins, play with the spice level, and customize the toppings to fit your family’s taste. Whether you’re feeding a crowd for brunch or stocking the fridge with grab‑and‑go squares for the week, this casserole holds up beautifully.

Ingredients for the Homemade Southwest Breakfast Casserole

Below is a quick tour of the key ingredients I use and why they matter in the casserole. I’m not listing quantities here—those are all waiting for you in the printable recipe card—but this should help you understand how each ingredient earns its place.

Eggs
The backbone of the casserole. Eggs set into a soft, custardy base that holds all the fillings together while still staying tender and fluffy.

Breakfast sausage
I like using bulk pork breakfast sausage for its built‑in seasoning. It adds richness, protein, and a savory, slightly spicy flavor that balances the eggs and cheese.

Frozen shredded hash browns
Hash browns create a hearty, potato‑y layer that makes this casserole feel like a complete breakfast in one slice. They soak up flavor from the sausage and spices while staying pleasantly tender.

Shredded cheddar cheese
Sharp cheddar melts into creamy pockets throughout the casserole and forms a golden, bubbly top. It’s the cheesy glue that ties all the Southwest flavors together.

Bell peppers
I use a mix of red and green bell peppers for color and sweetness. They soften in the oven but still keep a little bite, adding freshness to each forkful.

Onion
A sautéed onion brings gentle sweetness and depth. It blends into the background but makes the entire casserole taste more rounded and savory.

Canned diced green chiles
These mild chiles bring a tangy, peppery warmth without blowing out anyone’s taste buds. They layer in that classic Southwest flavor and play so well with the sausage and cheese.

Sliced black olives
Black olives add a salty, briny pop that cuts through the richness of the eggs and cheese. I scatter some inside the casserole and a few more on top.

Whole milk or half‑and‑half
Whisked with the eggs, milk (or half‑and‑half) creates a custard that bakes up luxuriously soft instead of rubbery. It’s the secret to that velvety texture.

Chili powder & ground cumin
These pantry spices bring warmth, smokiness, and that unmistakable Southwest aroma. They season the potatoes and eggs without making the dish overly spicy.

Salt & black pepper
Simple, but essential. They make the flavors pop and keep the eggs from tasting flat.

Green onions
I love finishing the casserole with a sprinkle of sliced green onions. They add a bright, fresh crunch and a little hint of sharpness.

How To Make the Homemade Southwest Breakfast Casserole

Step 1 – Prep the Baking Dish and Hash Browns

Start by lightly greasing a 9×13‑inch baking dish with butter or cooking spray. Spread the frozen shredded hash browns in an even layer on the bottom of the dish. I like to break up any clumps so they bake up evenly and soak in all the flavor from the sausage and egg mixture.

Step 2 – Brown the Sausage and Sauté the Veggies

In a large skillet over medium‑high heat, cook the breakfast sausage, breaking it up with a spatula as it browns. Once it’s mostly cooked through, add the diced onion and bell peppers. Sauté until the sausage is fully cooked and the vegetables are softened and just starting to caramelize around the edges.

If there’s a lot of excess grease in the pan, drain it off so the casserole doesn’t turn out greasy.

Step 3 – Layer the Savory Fillings

Spoon the hot sausage and veggie mixture evenly over the bed of hash browns in your baking dish. Sprinkle the canned diced green chiles and sliced black olives over the top. This layering keeps the flavors distributed so every slice has a bit of everything.

Step 4 – Whisk the Egg Mixture

In a large mixing bowl, whisk together the eggs, milk or half‑and‑half, chili powder, cumin, salt, and black pepper. Whisk until the mixture is smooth, well combined, and slightly frothy—this helps the casserole bake up light and fluffy.

Step 5 – Add the Cheese and Pour

Stir about half of the shredded cheddar cheese into the egg mixture. Then slowly pour the egg mixture over the sausage and hash brown layers, tilting the pan a little if needed to help it settle into all the corners. Sprinkle the remaining cheese evenly over the top.

Step 6 – Chill (Optional) or Bake Right Away

At this point, you have two options. You can cover the casserole and refrigerate it overnight for an easy make‑ahead breakfast, or slide it straight into a preheated oven. I often assemble it the night before so the flavors mingle and the morning feels effortless.

Bake at 350°F (175°C) until the center is set and the top is golden and bubbly. You’ll know it’s done when a knife inserted in the center comes out mostly clean and the edges are slightly puffed.

Step 7 – Rest, Garnish, and Serve

Let the casserole rest for about 10 minutes after it comes out of the oven. This brief pause helps it set up so you can cut neat squares. Just before serving, scatter sliced green onions over the top for a fresh, colorful finish.

Serving and Storing Homemade Southwest Breakfast Casserole

I usually cut this casserole into generous squares and serve it warm right out of the pan. It’s hearty enough to be the main event at breakfast or brunch, and leftovers make a fantastic grab‑and‑go lunch with a simple side salad.

To store leftovers, let the casserole cool completely, then cover the dish tightly or transfer slices to airtight containers. It keeps well in the refrigerator for up to 4 days. Reheat individual pieces in the microwave until warmed through, or pop them into a 325°F oven for a few minutes if you prefer the edges a little crisp.

This casserole also freezes beautifully. Wrap cooled squares individually, then stash them in a freezer bag or container. When you need a fast breakfast, thaw overnight in the fridge and reheat, or reheat gently from frozen, adding a few extra minutes.

What to Serve With Homemade Southwest Breakfast Casserole?

Fresh Fruit Salad

A bright fruit salad with berries, pineapple, and citrus adds a juicy, refreshing contrast to the rich, cheesy casserole.

Crispy Bacon or Breakfast Sausage Links

If your crowd loves extra protein, serve a platter of bacon or sausage links alongside. The smoky, salty bite pairs perfectly with the Southwest spices.

Warm Tortillas or Toasted Bread

Soft flour tortillas, warm corn tortillas, or thick slices of toasted sourdough are great for scooping up the casserole or turning leftovers into breakfast sandwiches.

Simple Green Salad with Lime Vinaigrette

For a brunch spread, I like to balance the casserole with a crisp green salad dressed in a tangy lime vinaigrette. It keeps the meal feeling fresh and light.

Salsa, Guacamole, and Hot Sauce

Set out bowls of salsa, chunky guacamole, and your favorite hot sauce so everyone can customize their slice. A spoonful of pico de gallo or a drizzle of spicy sauce wakes up the flavors.

Breakfast Potatoes or Roasted Sweet Potatoes

If you’re feeding a big group, roasted breakfast potatoes or Southwest‑style sweet potatoes make the table feel extra abundant and cozy.

Want More Savory Breakfast Ideas?

If you love this Homemade Southwest Breakfast Casserole, you’ll probably enjoy these other breakfast favorites from the blog:

Nutella French Toast Casserole when you’re craving a chocolaty, dessert‑for‑breakfast kind of brunch.
Christmas Breakfast Casserole for holidays and special mornings when you need something hearty and festive.
French Toast Casserole with Croissants for an ultra‑buttery, bakery‑style baked French toast.
Cinnamon Roll French Toast Bites when you want a sweet little bite to round out your breakfast spread.

These dishes all play well together on a brunch table, so feel free to mix and match them for your next weekend gathering.

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If you try this casserole, let me know how it turned out for you. Did you dial up the heat with extra chili powder, swap in chorizo, or load it with more veggies?

I love hearing how you make these dishes your own. Drop your tweaks and questions in the comments so we can keep sharing new breakfast ideas together.