Cheesy Sausage Breakfast Casserole is a perfect breakfast bake made with eggs, sausage, cheddar, baby spinach, and potatoes O’Brien. Great for weekends and holidays, it’s a meal the whole family will love!

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Cheesy Sausage Breakfast Casserole after it has baked.

Like my husband, my kids could eat eggs every day. To not deprive my egg-loving family of a food they love, I created this Cheesy Sausage Breakfast Casserole because it’s something that we can all enjoy.

Sausage and cheese go hand-in-hand in a breakfast casserole, but I wanted to add some fresh baby spinach to sneak in a veggie.

You could also easily throw in some sautéed mushrooms, pickled or fresh jalapeno, or just about any kind of non-watery vegetable you want.

Ingredients needed (scroll down to recipe card for the complete recipe):

Frozen potatoes O’Brien
Eggs
Shredded cheese – something melty like cheddar or a Mexican blend
Milk – regular and oat milk work great
Fresh baby spinach
Hot sauce (optional)
Chives
Seasonings (salt, garlic powder, onion powder, black pepper, white pepper)

📍The full recipe with exact ingredient amounts and instructions is on the recipe card at the bottom of the post.

I love using potatoes O’Brien instead of hash browns in this casserole because in addition to potato, you also get onion, red bell pepper, and green bell pepper.

It’s an easy way to sneak in more veggies and an effortless way to get more flavor.

How to make Cheesy Sausage Breakfast Casserole:

1. Put potatoes O’Brien in the bottom of a greased 9×13 baking dish.

Potatoes o'Brien in a baking dish, which is the bottom layer of Cheesy Sausage Breakfast Casserole

2. Add some cooked breakfast sausage on top of the potatoes O’Brien.

Potatoes o'Brien topped with cooked and crumbled sausage in a baking dish, the second step for making of Cheesy Sausage Breakfast Casserole

3. Add a layer of your favorite shredded cheese on top of the sausage.

Potatoes o'Brien topped with cooked and crumbled sausage and shredded cheese in a baking dish, the third step for making of Cheesy Sausage Breakfast Casserole

4. Then add a layer of torn baby spinach leaves on top of the sausage/cheese layer.

Potatoes o'Brien topped with cooked and crumbled sausage, shredded cheese, and spinach in a baking dish, the fourth step for making of Cheesy Sausage Breakfast Casserole

5. Pour the egg/milk mixture over everything, top with shredded cheese, and bake in the oven until the eggs are fully cooked and the cheese is melted and a nice golden color.

Cheesy Sausage Breakfast Casserole after it has baked and come out of the oven.

How to serve Sausage Breakfast Casserole

This casserole is a great weekend breakfast or brunch!

We almost always have it on Christmas morning, but my family loves it so much, we sometimes have it for “brinner” (breakfast for dinner).

Cheesy Sausage Breakfast Casserole is great served with fresh fruit, and we always have some homemade Habanero Hot Sauce with it.

What kind of sausage is best?

I use pork breakfast sausage in this recipe, but turkey sausage, or plant-based sausage crumbles would also be great in this recipe.

What are potatoes O’Brien?

A lot of readers from outside the U.S. ask me what potatoes O’Brien are, so I thought I’d add that info here. They are frozen potatoes, onion, and bell peppers all diced in the same uniform size.

They come in a bag in the frozen section of the grocery store and are great for frying in a pan for breakfast. I use them as the base layer for this casserole!

Looking for more breakfast recipes? Here are some favorites:

💡 Tips & Tricks

This recipe uses half a bag of frozen potatoes O’Brien. Feel free to double the recipe with two casserole dishes, or save the other half for another day!
Milk: I have tested this with regular milk and oat milk with success!

A slice of Cheesy Sausage Breakfast Casserole on a white plate.

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