This gluten free, Whole30, and paleo Italian Sausage Breakfast Casserole is a healthy, protein- and veggie-packed way to jumpstart your morning!
Table of Contents
- Breakfast for anytime of the day!
- Ingredients
- How to make Italian Sausage Breakfast Casserole
- Heat the oven and cook the casserole filling
- Whisk together the egg mixture
- Assemble the sausage breakfast casserole
- Bake the breakfast casserole
- Slice and serve!
- Can you make this casserole ahead of time?
- More Paleo and Whole30 easy breakfast casserole recipes
- Italian Sausage and Mushroom Breakfast Casserole (Whole30, Gluten Free) Recipe
Breakfast for anytime of the day!
If you’re looking for a delicious, make-ahead savory breakfast, make this hearty and comforting Italian Sausage and Mushroom Breakfast Casserole! Not a breakfast person? No worries! This deliciously easy casserole features the same flavor profile as my favorite pizza—one loaded with sausage and mushrooms—so it’ll taste great any time of day!
Ingredients
- Large eggs
- Italian sausage: mild or hot bulk Italian sausage or breakfast sausage works great in this recipe. If you can’t find a Whole30-compatible version at the store, make my homemade Italian sausage recipe. Want to cut down on the cooking time? Slice up some cooked sausage links and use it in place of bulk Italian sausage.
- White or brown button mushrooms: You can use your favorite type of mushrooms in this casserole, but good ol’ white or brown button mushrooms are just fine. Is there a better combination than sausage and mushrooms? (Answer: nope!)
- Baby spinach: Personally, I love the ease of tossing baby spinach into this casserole—but you can just as easily substitute another vegetable (e.g., chard, kale, chopped broccoli, diced bell peppers, etc.).
- Shredded white sweet potatoes: In place of stale bread or store-bought hash browns, I like using shredded white sweet potatoes in this casserole. If you can’t find Hannah sweet potatoes, you can use shredded orange sweet potatoes or yellow potatoes. Alternatively, to make a lower carb casserole, you can use broccoli slaw or cauliflower rice.
- Marinara sauce: Adding marinara sauce makes this breakfast casserole taste even more like my favorite sausage and mushroom pizza! My favorite brand of Whole30-compatible store-bought marinara sauce is always and forever Rao’s.
- Coconut milk, almond milk, cashew milk, or favorite non-dairy milk: In place of heavy cream or milk, I use any unsweetened non-dairy milk that I have on hand. The added creamy liquid makes the casserole fluffy and not rubbery.
- Nutritional yeast: I use this vegan staple to replace cheddar cheese in this casserole. You can leave it out, but it really does add to the deliciousness of this casserole.
- Dried basil: At a minimum, I add some dried basil to flavor this breakfast casserole—but feel free to add Italian seasoning or your favorite fresh herbs to yours.
- Garlic
- Onion
- Extra virgin olive oil
- Magic Mushroom Powder or Diamond Crystal kosher salt: Magic Mushroom Powder adds the perfect umami punch to this casserole, but regular kosher salt will also work. You can buy Magic Mushroom Powder on Amazon or at The Spice Lab!
- Freshly ground black pepper
- Avocado oil spray
How to make Italian Sausage Breakfast Casserole
Heat the oven and cook the casserole filling
Heat oven to 400°F with the rack in the middle. While the oven is warming up, heat a large 12-inch skillet over medium heat and swirl in the extra virgin olive oil when the pan is hot. Add the onion and mushrooms and ½ teaspoon of Magic Mushroom Powder or Diamond Crystal kosher salt.
Cook the vegetables for about 8 to 10 minutes, stirring frequently, or until the liquid released from the mushrooms has evaporated.
Throw in the minced garlic and sauté until fragrant, about 30 seconds.
Add the Italian sausage and use a spatula to break it up. Cook, stirring frequently, until the sausage crumbles are no longer pink, about 5 minutes. You can drain the fat if you wish, but I just leave it in.
Toss in the baby spinach and stir until slightly wilted.
Take the pan off the heat and mix in the grated sweet potatoes and marinara sauce.
Stir to combine and then set aside to cool slightly.
Whisk together the egg mixture
In a large bowl, whisk together the eggs, coconut milk, nutritional yeast, basil, 1 teaspoon Magic Mushroom Powder or Diamond Crystal kosher salt, and ¼ teaspoon black pepper.
Assemble the sausage breakfast casserole
Grease a 9-inch x 13-inch casserole pan with avocado oil spray. Transfer the cooked sausage and vegetables to the pan and spread the contents evenly.
Pour the egg mixture evenly on top of the sausage and veggies.
Bake the breakfast casserole
Pop the casserole in the oven and bake for 35 to 40 minutes, rotating the tray at the halfway point.
The casserole is finished when the top is golden and a toothpick comes out clean when inserted in the middle.
Slice and serve!
Take the baking dish out of the oven and leave it to cool for 5 to 10 minutes. Then, slice it up and enjoy!
Can you make this casserole ahead of time?
Yes! This sausage breakfast casserole recipe can be made ahead and stored in a sealed container in the refrigerator for up to 4 days. You can also wrap up the individual slices and freeze them for up to 4 months. (If you freeze leftovers, you can thaw the slices in the fridge overnight.) I reheat the slices in my Anyday microwave bowls by zapping them on high for about 1 minute or until heated through.
More Paleo and Whole30 easy breakfast casserole recipes
Looking for more recipe ideas? Head on over to my Recipe Index. You’ll also find exclusive recipes in my cookbooks, Nom Nom Paleo: Food for Humans (Andrews McMeel Publishing 2013), Ready or Not! (Andrews McMeel Publishing 2017), and Nom Nom Paleo: Let’s Go! (Andrews McMeel Publishing 2022)
Italian Sausage and Mushroom Breakfast Casserole (Whole30, Gluten Free)
Ingredients
- 2 tablespoons extra virgin olive oil
- 1 medium onion finely chopped
- ½ pound cremini mushrooms thinly sliced
- Magic Mushroom Powder or Diamond Crystal kosher salt
- 5 garlic cloves minced
- 1 pound bulk Italian sausage
- 4 ounces baby spinach about 4 cups
- Freshly ground black pepper
- 3 cups shredded white sweet potatoes (e.g. Hannah variety)
- 1 cup marinara sauce
- 12 large eggs
- ¼ cup full-fat coconut milk or another non-dairy milk
- ¼ cup nutritional yeast
- 1 teaspoon dried basil
- ¼ teaspoon Freshly ground black pepper
- Avocado oil spray
Instructions
- Heat oven to 400°F with the rack in the middle. While the oven is warming up, heat a large 12-inch skillet over medium heat. Swirl in the extra virgin olive oil when the pan is hot.
- Add the onion and mushrooms. Sprinkle ½ teaspoon Magic Mushroom Powder or Diamond Crystal kosher salt on the vegetables and cook for about 8 to 10 minutes, stirring frequently until the liquid released from the mushrooms has evaporated.
- Throw in the minced garlic and sauté until fragrant, about 30 seconds.
- Dump in the Italian sausage and use a spatula to break it up. Cook, stirring frequently, until the meat is no longer pink, about 5 minutes.
- Toss in the baby spinach and stir until slightly wilted.
- Take the pan off the heat and mix in the grated sweet potatoes and marinara sauce. Stir to combine and set aside to cool slightly.
- In a large bowl, whisk together the eggs, coconut milk, nutritional yeast, basil, 1 teaspoon Magic Mushroom Powder or Diamond Crystal kosher salt, and ¼ teaspoon black pepper.
- Grease a 9-inch x 13-inch casserole pan with avocado oil or olive oil spray. Transfer the cooked sausage and vegetables to the pan and spread the contents evenly. Pour the egg mixture on top.
- Pop it in the oven and bake for 35 to 40 minutes, rotating the tray at the halfway point. The casserole is finished when the top is golden and a toothpick comes out clean when inserted in the middle.
- Take the casserole out and leave it to cool for 5 to 10 minutes. Then, slice it up and serve!
Video
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Michelle, it’s really helpful when you post a photo showing all the ingredients arranged like a poster, much easier than scanning a list and risking missing something. Thank you!!
You’re welcome!
We are always looking for a savory breakfast option. This looks delicious, thank you!
Can you substitute turnip or rutabaga for the sweet potato?
I have not tried. My best suggestions for subs would be yellow potatoes, broccoli slaw or cauliflower rice.
This Italian Sausage Breakfast Casserole is a great way to start the day. It’s packed with flavor and protein, and makes a great meal for brunch, breakfast, or dinner. The combination of sausage, eggs, cheese, and veggies makes it a delicious and filling dish. Loved your recipe!!
– Jack from Skilletguy.com
Thank you Jack!
Do I really need nutritional yeast? I’m super-excited to try this, and since I’m not 100% Paleo (I do OK with limited amounts of dairy) is a bit of Peccorino Romano or Parmigiano Reggiano OK in its place?
You can use cheese in place of nutritional yeast!
Made this today for a Brunch and everyone loved it and several want the recipe. Never used Nutritional Yeast before and love the flavor it provides. Delicious!!
I love recipes like this to feed a crowd and italian sausage is always a hit.
This was SO delicious and my husband and I were completely happy eating an entire recipe of this by ourselves throughout the week. Filling with great flavor – a total keeper in our rotations.
Thanks Tracy!
Loving the idea of this recipe, but wanting it not to taste like pizza. Would replacing the marinara sauce with sliced cherry tomatoes change the consistency too much?
It should be fine, but if it seems too dry you can add a few eggs.