Spinach Feta Chicken Sausage Breakfast Casserole

Spinach, feta, chicken sausage and mushrooms baked together with eggs and mozzarella cheese! Perfect for brunch or meal prep, you’ll love this Spinach Feta Chicken Sausage Breakfast Casserole with a sweet potato crust!

The original concept for this Spinach Feta Chicken Sausage Breakfast Casserole with a sweet potato crust is from the spinach feta breakfast wraps at Starbucks. I love the spinach feta combo, so I made it into an entire casserole!

The most unique thing about this casserole? The crust. It’s made from thin slices of sweet potato, layered and baked ahead of time to soften up and become a simple veggie crust.

Of course, if you’re not into sweet potatoes, you can always replace with a normal quiche crust, phyllo dough, or just skip it entirely! But if you like sweet potatoes, this is a fun way to incorporate them into breakfast!

What are the ingredients in this Spinach Feta Chicken Sausage Breakfast Casserole?

If you love those spinach feta breakfast wraps from Starbucks, you’ll probably love this breakfast casserole. It’s packed with veggies and chicken sausage, baked in eggs and cheese, all over a layered sweet potato crust.

Here’s a little more information on each of the ingredients I used in this recipe:

• sweet potato – Use one large or two medium sweet potatoes for the crust. I think thicker sweet potatoes are easier to use for this but any will work as long as there are enough discs to cover the bottom of the dish with 2-3 layers.
• avocado oil – I like to use avocado oil to saute the meat and veggies, but olive oil would also work for this recipe.
• Italian seasoned ground chicken sausage – Look for this in the ground meat section of the grocery store, near the ground turkey. If they don’t have Italian seasoned ground chicken, you can use plain ground chicken and add Italian seasoning.
• white mushrooms & yellow onion – To add some bulk to the casserole, I added mushrooms and onions to the sauteed veggie party. You could also swap these out for your favorite veggies!
• baby spinach leaves – Toss in a few cups of baby spinach leaves to the veggies at the end and they’ll wilt down. Spinach and feta is one of my favorite savory combos!
• garlic powder & red pepper flakes – Adding these spices helps bring more flavor and spice (if you want) to the casserole.
• fine sea salt & fresh ground black pepper – All egg dishes need a bit of salt and pepper to enhance flavor, this casserole is no exception. Fresh ground black pepper is the best!
• eggs – Of course, we need eggs to make a baked egg casserole.
• milk – Adding a bit of milk slightly reduces the concentration of egg which balances flavors. It also, makes a creamier texture overall.
• feta cheese – I love how the feta makes little pockets of salty creamy cheese in the casserole. It’s a perfect balance to the sweet potato crust.
• mozzarella cheese – To keep it easy, buy a bag of pre-shredded mozzarella for this recipe. It gets nice and crisp on the top of the casserole. Perfect way to finish it off!

How do you make the sweet potato crust?

I’m very much in love with this sweet potato crust method. It’s a totally unique and unexpected way to use sweet potatoes, and makes a good alternative crust for the flavors in this casserole.

You can use either one long sweet potato, or two smaller ones. Slice the sweet potato into super thin discs, about an 1/8 of an inch thick. You can use a mandoline slicer if you have one, which makes this task super efficient. Don’t forget to use that guard!

Once you’ve sliced the sweet potatoes, spray a 9×13 inch casserole dish with non-stick cooking spray (or wipe with avocado oil) and layer the discs in the casserole dish until you run out of sweet potato.

I like to break a few discs in half and put the straight edge against the casserole dish to cover all the edges. It’s that simple! Make sure you can’t see the bottom of the dish, and then bake it for 20-25 minutes at 375F degrees. Start with the lowest time and check from there. If any of the edges are burning or the pieces are starting to curl, it’s time to take it out!

How do you make this Spinach Feta Chicken Sausage Breakfast Casserole?

After you get the sweet potato crust going in the oven, the rest of the casserole is super simple to cook up and put together. You guessed it – cook the meat and veggies, layer it with the eggs and cheese, then bake!

In a Dutch oven or another large pan that can handle lots of meat and veggies, add the oil and heat it over medium heat. Cook the chicken sausage, breaking it up as you go, until it’s completely cooked through.

Once it’s cooked with no more visible pink, add the mushrooms and onions. Cook everything for a few more minutes, stirring occasionally as you go. I like to use a wooden spatula or spoon and break up the mushroom slices even further if they seem a bit big.

After the onions have turned translucent and the mushrooms have shrunk a bit, finish it off the the spinach and seasonings. Stir it together and cook for just another minute until the spinach is wilted and bright green.

Set the meat and veggies aside to cool for a minute while you whisk the eggs, milk and remaining salt and pepper together. Once the crust is done, it’s ready to assemble.

Use a slotted spoon so none of the extra moisture from the cooked veggies goes into the casserole. Spread about half of the cooked mixture over the sweet potato crust. Sprinkle 1 cup of the mozzarella and about half of the feta on top, then pour about half the eggs over everything in the dish.

Repeat the pattern once more and finish it off with cheese on top. Bake the casserole in the preheated oven for 35-45 minutes, checking after the minimum time to see how it looks.

The casserole is done when the center is set and no longer jiggly when you move the dish. The baked egg will also start to pull away from the sides a bit. Let it cool for about 5 minutes, then serve!

Best tips for making this Spinach Feta Chicken Sausage Breakfast Casserole:

Here are my best tips to help you succeed when making this Spinach Feta Chicken Sausage Breakfast Casserole:

• Stick with Italian seasoned ground chicken, and if it’s not available, be sure to add additional seasoning. This adds way more flavor to the casserole than using a plain ground meat.
• If you’re planning to reheat this casserole for meal prep, it’s okay if it’s *slightly* undercooked, as the eggs will cook a bit more during reheating.
• Grease your pan well using non-stick spray or wipe some avocado oil all over the bottom and sides. The sweet potato crust helps the eggs not stick to the bottom, but you should grease the sides well too!
• Swap the veggies if you want! Just be sure to remove as much excess liquid as possible before adding them into the casserole.

Can I use different breakfast meat in this casserole?

Yes! Another great option would be seasoned ground pork sausage, or cooked and chopped bacon. Just be sure to add some Italian seasoning if you use plain ground meat.

What should you serve with this casserole?

This casserole could be served on it’s own as a whole breakfast but I also like to add fruit to the side for serving! Top with some hot sauce for the best experience!

How do you meal prep this recipe?

Here are some ideas on how to meal prep this recipe at your house:

1. Ingredient prep: Prep the veggies, including slicing the sweet potato, cutting onions and mushrooms, and measure out all spices ahead of time. You could also crack the eggs into a jar with lid and mix in the milk to save a couple minutes there as well. Have everything ready to go so you can assemble and cook the casserole in the next 24 hours or so.
2. Prep for now & later: Prepare the recipe as written and enjoy a portion or two now, while saving the rest for additional meals in the next 4 days. Since this recipe makes 8 portions, this works better if you have more than one person in your house!
3. Complete prep & portion: Prepare the recipe as written and portion the casserole into containers with lids or freezer safe containers and store as noted below.

How to store Spinach Feta Chicken Sausage Breakfast Casserole:

Store leftovers in an airtight container with lid in the fridge for up to 4 days for best quality.

How to reheat Spinach Feta Chicken Sausage Breakfast Casserole:

Reheat individual servings in the microwave covered for 60-90 seconds until heated through. Alternatively, reheat covered in the oven at 350F for about 20 minutes until heated through.

How to freeze Spinach Feta Chicken Sausage Breakfast Casserole:

Freeze individual portions wrapped in foil then stored in a freezer safe bag or container for up to 3 months for best quality. Let it thaw in the fridge overnight before you plan to eat it, and then reheat as normal.