Slow Cooker Breakfast Casserole

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This slow cooker breakfast casserole is the perfect make-ahead meal for busy mornings or a cozy weekend brunch. It’s easy to customize with your favorite add-ins, making it a warm and hearty dish for any gathering.

A slice of slow cooker breakfast casserole on a small dish, garnished with greens

Table of Contents

There’s nothing better than waking up to a warm, homemade breakfast that’s ready to enjoy.

When you have guests or a busy morning ahead, it’s nice to have something simple you can prep the night before that’s both nourishing and delicious.

That’s why this slow cooker breakfast casserole has become a staple in our house for holidays, hosting overnight guests, and even lazy weekend mornings.

Sometimes this dish is called a breakfast bake or overnight breakfast casserole, but no matter what you call it, it’s a true crowd-pleaser and so easy to customize with all your family’s favorite veggies, meats, and cheeses.

This meal is the perfect make-ahead recipe when you need something ready to go in the morning. Just prep everything the night before, set it to cook, and wake up to breakfast already taken care of.

Enjoy this with home-cured brown sugar and pepper bacon or coffee with delicious vanilla and brown sugar creamer.

Why You’ll Love This Recipe

Easy: Make this casserole with simple ingredients and prep the night before for an effortless morning meal.

Crowd-Friendly: Perfect for brunches, holiday mornings, or feeding a house full of family and friends.

Customizable: This is a great base recipe that can be made with any veggies, meats, or different cheeses your family loves.

Kid-Approved: Made with everyday ingredients and familiar flavors, this recipe is a hit with even the pickiest of eaters.

Meal Prep: Prepare it in advance for a homemade breakfast that’s ready to go for the rest of the week. This is a great recipe for a Sunday reset.

Ingredients

Eggs: Eggs make the base of the casserole and give it a soft, fluffy texture. You can also use freeze-dried eggs for this recipe.

Sausage: Ground breakfast sausage adds delicious flavor and makes the dish hearty and satisfying without having to add extra spices (unless you want to!).

Veggies: I used onions, green peppers, and potatoes. But you can use your favorites or any veggies you have on hand.

Cheese: I used Parmesan, but feel free to swap another cheese you enjoy, such as cheddar or mozzarella.

Milk: I used whole milk, but reduced-fat milk will also work.

Get the full list of ingredients and measurements on the printable recipe card below.

Tools You Will Need

Skillet: You’ll need a large skillet to brown the sausage and sauté the veggies. I use a 13.25″ Lodge cast iron skillet.

Slow Cooker: Any slow cooker will work for this recipe. I use a Brod & Taylor proofer and slow cooker with a covered casserole dish as the insert.

Step-by-Step Instructions

Note: My slow cooker uses a regular baking dish, so the images show a casserole dish. Use your regular slow cooker insert for this recipe.

Ground sausage browning in a cast iron skillet, shown with wooden spatula

Step 1: In a large skillet, brown the ground breakfast sausage over medium-high heat.

Season with salt and pepper to taste. Drain the excess fat if necessary.

Onions, peppers, and potatoes on browned sausage in skillet, shown with wooden spoon

Step 2: Toss in the onions, green peppers, and potatoes. Cook for about 5 minutes, until the onions are soft and translucent.

Transfer the sausage and veggie mixture to the slow cooker insert and set aside.

Eggs and milk in a mixing bowl, shown with a whisk in the bowl and egg shells in the background

Step 3: In a large mixing bowl, whisk together the eggs and milk until thoroughly combined. Season with salt and pepper to taste.

Sausage and egg mixture in a pot with parmesan cheese on top

Step 4: Pour the egg mixture into the slow cooker with the sausage and veggies. Add the Parmesan cheese, then stir everything together gently to combine.

Overhead of finished slow cooker breakfast casserole, shown with a serving spoon and a bowl of cracked egg shells

Step 5: Cover and cook on Low for 7–8 hours or High for about 4 hours, until the center is set and a knife inserted in the middle comes out clean.

Every slow cooker heats a little differently. Mine is usually done on Low in about 4 hours, so start checking around then.

Tips for Success

Try making this recipe during the day the first time to gauge your slow cooker’s timing. Mine cooks in about 4 hours, but some take up to 8. Then, you’ll know how to adjust for overnight.
Many sausage brands are seasoned well enough that you don’t need to add anything else, but you can always include your favorite herbs and spices if you’d like.
This recipe is great for meal prepping. Just reheat portions throughout the week for a quick and easy breakfast.
Swap or add ingredients based on what your family likes best.

Serving Suggestions

Sourdough: A slice of homemade sourdough toast is perfect alongside this casserole.

Fruit: Fresh fruit like berries, melon, or citrus adds a delicious balance to the hearty breakfast dish.

Brunch Tables: This casserole is perfect for brunch. Serve it with sourdough cinnamon rolls, pancakes, fresh fruit, and coffee for an easy, delicious spread.

Burritos: Scoop some warm casserole into a sourdough tortilla for a quick and flavorful breakfast burrito.

Egg Bowls: Layer in a bowl with your favorite toppings like fresh greens, salsa, shredded cheese, or even homemade sauerkraut.

A close up of a forkful of slow cooker breakfast casserole

Storing

After cooling, store leftovers in an airtight container and keep in the fridge for up to 4 days.
Reheat individual portions in the microwave or warm the whole dish in the oven until heated through.

Variations

Veggie Lovers: Load it up with extra veggies like spinach, mushrooms, or zucchini for a delicious, veggie-packed breakfast.

Meat Lovers: Add cooked bacon, ham, or extra sausage for a protein-filled version.

Cheesy: Mix in extra cheese like cheddar, mozzarella, or Swiss for an extra melty and rich casserole.

Southwest: Add black beans, peppers, corn, and a sprinkle of taco seasoning. Before serving, top with salsa or avocado.

Hashbrown: Swap the diced potatoes for store-bought hashbrowns for an easy, classic meal. I really like Azure Standard’s southern hashbrowns.

FAQs

Can I cook this overnight?

Yes, you can cook this casserole overnight! Set your slow cooker to low and let it cook for about 6-8 hours so it’s ready when you wake up.

Can I use frozen hash browns?

Yes, frozen hash browns work great in this recipe. There’s no need to thaw first. Just stir them in from frozen. If you prefer crispier edges, you can lightly brown them in a skillet before adding them to the crockpot.

Can I make this vegetarian?

Yes, you can easily make this casserole vegetarian. Just skip the sausage or replace it with a plant-based alternative. Load it up with extra veggies or add beans for plenty of flavor and heartiness without the meat.

Can I double the recipe?

Yes, you can double the recipe if you’re feeding a large gathering. Just make sure your slow cooker is large enough to handle the extra amount.

You may need to add extra cooking time and check for doneness toward the end to ensure the eggs are done in the center. If it’s taking a long time, you can pop it in the oven at 350° F for a few minutes before serving.

A fork piercing into a slice of slow cooker breakfast casserole

Let’s Connect!

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