Spinach Mushroom Breakfast Casserole Recipe

I absolutely love sharing this Spinach Mushroom Breakfast Casserole Recipe because it’s one of those meals that feels cozy and hearty but also fresh and packed with veggies. When I first tried making breakfast casseroles, I used to struggle getting the veggies cooked just right without making the dish soggy. This recipe cracked the code for me! It brings together tender mushrooms, wilted spinach, creamy cottage cheese, and sharp cheddar in a way that my whole family goes crazy for. Whether you’re prepping for a weekend brunch or meal prepping for busy mornings, you’ll find that this casserole is as delicious as it is forgiving to make.

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Ingredients You’ll Need

This Spinach Mushroom Breakfast Casserole recipe calls for everyday ingredients that complement each other beautifully. When shopping, pick fresh mushrooms with no bruising and bright green spinach for the best flavor and texture.

• Unsalted butter: Using unsalted butter lets you control the salt level more precisely in this savory dish.
• Medium onion: I like to use yellow onions for their sweetness when sautéed.
• Mushrooms: White button or cremini mushrooms work great, just slice them thin for even cooking.
• Baby spinach: Feel free to substitute with fresh baby kale if you want a slightly earthier bite.
• Garlic cloves: Fresh minced garlic is key for that punch of flavor.
• Eggs: They’re the binder holding everything together—make sure they’re well-beaten.
• Cottage cheese: Adds creaminess and protein without heaviness.
• Sharp cheddar cheese: I always shred it fresh for that melty, rich flavor.
• Green onions: They give a subtle oniony freshness that lightens the casserole.
• Kosher salt and black pepper: Essential for seasoning and balance.

Variations

One of the things I love about this Spinach Mushroom Breakfast Casserole Recipe is how easy it is to customize. I often switch up the veggies or add a little extra protein depending on what we have on hand—so don’t be afraid to make it your own!

• Adding sausage or bacon: I once tossed in cooked crumbled sausage for a meatier brunch option, and my family adored it.
• Using different greens: Swiss chard or kale can brighten the flavor and texture beautifully if spinach isn’t your favorite.
• Cheese swaps: Try pepper jack or gruyere for a twist on the classic cheddar flavor.
• Make it dairy-free: Substitute cottage cheese with a silken tofu blend and use dairy-free cheese alternatives for a vegan spin.

How to Make Spinach Mushroom Breakfast Casserole Recipe

Step 1: Sauté your veggies to perfection

Start by heating 4 tablespoons of butter in a large skillet over medium heat. I like using a wide pan so the onions and mushrooms cook evenly without steaming. Once the butter is melted, toss in your chopped onion and sliced mushrooms. Stir them around for about 3-4 minutes until the onions turn translucent and the mushrooms soften up nicely. Next, add the minced garlic—this is where that fragrant garlicky punch kicks in—then sauté everything for just another minute.

Step 2: Wilt and prep the spinach

Now, add spinach by the handfuls right into the skillet. It will look like a ton at first, but it wilts down quickly. Cover your pan with a lid and let it cook for about 5 minutes until fully wilted. One trick I learned is to let the mixture cool for a bit, then gently squeeze out any excess liquid—this stops your casserole from turning watery. Once drained, chop the spinach and mushroom mixture a bit finer to spread the flavor evenly throughout.

Step 3: Combine everything in a bowl

In a separate large mixing bowl, whisk together the eggs, cottage cheese, shredded cheddar, sliced green onions, kosher salt, and black pepper. I find that whisking the eggs well ensures a fluffy, consistent texture. Then, fold in your cooled spinach and mushroom mixture until everything is evenly distributed. This mixture is already full of flavor and texture at this point, so you’re well on your way!

Step 4: Bake to golden perfection

Preheat your oven to 350°F and lightly grease a 13×9-inch baking dish with a tablespoon of butter. Pour your mixture into the dish and smooth out the top. Bake for 45 to 50 minutes until the top is a beautiful golden brown and the center is set. You can test doneness by inserting a toothpick or knife in the middle—it should come out clean or with just a few moist crumbs. I’ve found that letting it cool for a few minutes before slicing helps it hold its shape nicely.

How to Serve Spinach Mushroom Breakfast Casserole Recipe

Garnishes

I usually top servings with a sprinkle of freshly chopped parsley or additional sliced green onions. Sometimes, a little dollop of sour cream or a spoonful of salsa adds a delightful contrast that keeps things exciting. I love how these simple garnishes brighten up the rich casserole.

Side Dishes

For brunch, I like to serve this alongside crisp fruit salad or toasted multigrain bread. Roasted potatoes or a light mixed green salad also pair wonderfully to round out the meal. These sides keep the meal balanced and filling without overpowering the casserole.

Creative Ways to Present

For a special occasion, I’ve cut the casserole into muffin-sized portions using a greased muffin tin—it makes for a fun finger food presentation that’s great for kids or buffet-style brunches. You can even slide individual slices onto a bed of arugula with a drizzle of herb vinaigrette for a fancy plated look.

Make Ahead and Storage

Storing Leftovers

I keep leftover casserole tightly wrapped in airtight containers in the fridge, and it usually lasts for 3-4 days without losing flavor or texture. If your casserole has absorbed moisture by the second day, a quick reheat in the oven can refresh the crispy top.

Freezing

Freezing this casserole is a lifesaver when I make a big batch. I slice portions, wrap each tightly in plastic wrap and foil, then freeze. When you’re ready to eat, thaw them overnight in the fridge before reheating for best results. The texture holds up surprisingly well!

Reheating

To reheat, I prefer the oven to keep the texture intact—around 325°F for 15-20 minutes usually does the trick. If you’re in a hurry, microwaving works fine too, though the casserole gets softer. To regain some crispiness, pop it under the broiler for a minute or two afterward.

FAQs

Final Thoughts

This Spinach Mushroom Breakfast Casserole Recipe has become a staple in my kitchen because it balances simplicity with comforting flavor so well. Whether you’re feeding your family or prepping for the week ahead, this dish checks all the boxes: nourishing, easy, delicious, and adaptable. I really encourage you to give it a try—just imagine waking up to the smell of melted cheese, savory mushrooms, and fresh spinach baked into one perfect casserole. It’s a recipe that feels like a warm hug on a plate, and I’m confident you’ll love it as much as we do!

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