Sausage Egg Mushroom Casserole
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Want a filling and delicious make-ahead breakfast recipe? This easy-to-make sausage egg mushroom casserole has your name on it! This brunch recipe features a crispy potato and sweet potato crust, loaded with sausages, mushrooms, spinach, and eggs. It’s a delicious start to the day that allows you to savor more quality time with your loved ones.
I start this casserole with a base of sweet potato and regular potato hash, cooking it until it’s golden and crisp on the bottom. That crunchy layer is what makes the whole dish so satisfying.
Once the sausage, mushrooms, onions, and spinach are browned, everything gets piled onto the hashbrown crust and drenched in savory eggs. It bakes up cozy, hearty, and perfect for feeding a hungry crowd.
Ingredients needed
This egg sausage mushroom casserole is made from simple ingredients, free from any filler ingredients. This is what you need:
- Potato and sweet potato: Make a hash from the potato and sweet potato to create a hearty and delicious base with a crispy texture.
- Oil and butter: Imparts richness as you cook off the ingredients.
- Sausage: Use breakfast sausage or turn up the heat with fresh chorizo. You could even use Italian sausage!
- Mushrooms: For earthy and umami-rich depth of flavor.
- Red onion: Sautéed until sweet and aromatic. Yellow or white onion can be used if that’s what you have on hand.
- Baby spinach: Brings a burst of freshness.
- Eggs: Acts as a binding agent, bringing it all together.
Recipe FAQs
What type of sausage should I use in this sausage breakfast casserole?
We use breakfast sausage links and roughly chop them up before adding them to the frying pan.
Can I add anything else?
Sure! This sausage egg mushroom casserole is versatile – sprinkle some thyme or chives on top or add some cherry tomatoes or bell peppers. Grate some cheddar cheese and add to the egg mixture, or drizzle over some hot sauce before digging in!
What type of mushrooms should I use?
You can opt for whatever mushrooms you have in the fridge or find at the grocery store. We usually get cremini, button, or baby bella mushrooms.
Can I store any leftovers?
Absolutely! Keep it in an airtight container in the fridge for up to 3-4 days. You can eat it straight out of the fridge or reheat it in the oven.
Sausage Egg Mushroom Casserole Recipe
Ingredients
- 1 large potato
- 1 medium sweet potato
- 1 tablespoon EACH: oil and butter
- 1 lb breakfast sausage (chopped)
- 1 lb mushrooms (sliced)
- 1 small red onion (sliced)
- 10 ounces baby spinach
- 12 large eggs
- 1 teaspoon sea salt
- ½ teaspoon black pepper
Instructions
- Place the potato and sweet potato into a pot and cover with water. Bring to a boil then reduce the heat and simmer until soft but not falling apart. Drain and set aside to cool, preferably in your fridge. When they’re cold, peel and then grate them.1 large potato, 1 medium sweet potato
- Turn your oven to 350 degrees Fahrenheit. Heat the oil and butter in a large frying pan. Add the grated potatoes and cook, turning a few times, until there are lots of dark and crispy spots on the hashbrowns. Transfer them to a 9×11" casserole dish and press to create a crust.1 tablespoon EACH: oil and butter
- Add the sausage to the same pan you used for the potatoes. Cook until it is well browned, about 10 minutes. Transfer to the casserole dish.1 lb breakfast sausage
- Add the mushrooms to the pan and cook until they are browned, about 10 mins. Add them to the casserole.1 lb mushrooms
- Cook the onion until it is soft and golden, about 5 minutes. Add the spinach and let it wilt. Add both to the casserole and gently mix, being careful not to disturb the crust.1 small red onion, 10 ounces baby spinach
- Whisk the eggs in a large bowl with the salt and pepper. Pour the eggs over the casserole and carefully mix.12 large eggs, 1 teaspoon sea salt, ½ teaspoon black pepper
- Bake for 30 minutes, or until the casserole has set in the center.
Nutrition
We have thoroughly tested this recipe for accuracy. However, individual results may vary. See our full recipe disclosure here.
Can I prep this and freeze before baking?
Potatoes don’t freeze very well – they become gritty tasting – so I don’t recommend that.
How large a baking dish do you need for this recipe? I’m not a spinach fan. Do you think baby kale would work?
This will fit in a baking dish that is 9″x 11″. And I think baby kale will work perfectly!
That’s so great to hear!!
Do you use breakfast sausage? I’m confused by the “chopped sausage.” I can’t wait to try this recipe! Thanks!
That’s right! Just use 1 lb. of breakfast sausage and roughly chop it before you fry it. 🙂
Made the Sausage and Egg Breakfast Bake for brunch Christmas Morning. It was delicious! Thanks Kristen for a recipe that satisfied my husband as well as my daughter and me who like to eat Whole30.
So nice to have something lighter yet hearty to start the day with, isn’t it?!