Spinach Mushroom Breakfast Casserole: A Delicious, Wholesome Way to Start Your Day

There’s something undeniably comforting about a breakfast casserole. It brings together a medley of ingredients into a dish that feels both indulgent and nourishing at the same time. When you combine spinach, mushrooms, and goat cheese, and top it all with fluffy eggs, the result is a breakfast that’s rich in flavor, easy to prepare, and guaranteed to satisfy even the hungriest of guests. The Spinach Mushroom Breakfast Casserole is the perfect dish to serve for breakfast or brunch, offering a combination of fresh vegetables and creamy cheese with the soft, delicate texture of eggs. Whether you’re feeding a family, hosting a brunch gathering, or looking for a filling, savory breakfast for yourself, this casserole is the perfect choice.

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Why You’ll Love This Casserole

This casserole is a celebration of vegetables, with the earthy flavors of cremini mushrooms, the mild bitterness of spinach, and the rich tang of goat cheese all coming together beautifully. The eggs tie everything together, creating a soft and fluffy base that complements the sautéed vegetables perfectly. What makes this casserole stand out is its simplicity. It’s easy to make, requires minimal prep time, and uses a handful of wholesome ingredients. Plus, the best part is that you can prepare it ahead of time and bake it when you’re ready, making it a great option for busy mornings or when you’re entertaining guests.

There’s also something comforting about a casserole—everything is baked in one dish, and you don’t have to worry about multiple pots or pans. This dish can be customized to suit your taste or dietary preferences, allowing you to experiment with different cheeses, vegetables, and herbs. No matter how you decide to tweak it, this Spinach Mushroom Breakfast Casserole is sure to impress.

The Ingredients: What You’ll Need

Before diving into the recipe, let’s take a closer look at the key ingredients that come together to make this casserole so flavorful.

• Olive Oil: A tablespoon of olive oil is used to sauté the mushrooms and garlic, giving them a lovely depth of flavor. Olive oil is an essential base for many savory dishes, and in this recipe, it helps infuse the mushrooms with a subtle richness.
• Cremini Mushrooms (16 ounces): The mushrooms are the star of the show in this casserole. They bring an earthy flavor and a meaty texture that adds a savory foundation to the dish. Cremini mushrooms, also known as baby bella mushrooms, have a richer taste than white mushrooms, making them perfect for this recipe. You can substitute them with other types of mushrooms like white button mushrooms, portobello, or shiitake, depending on what you have available or your flavor preferences.
• Spinach (4 cups packed): Fresh spinach adds both color and a nutritious punch to the casserole. Its mild flavor doesn’t overpower the other ingredients, but it blends beautifully with the mushrooms. If you don’t have fresh spinach, you could use frozen spinach as a substitute, though it may change the texture slightly. Be sure to thaw and drain the frozen spinach thoroughly before using it.
• Garlic (3 cloves, minced): Garlic is a fundamental ingredient in this casserole. It adds an aromatic punch to the sautéed mushrooms and spinach, infusing the entire dish with its rich, savory flavor. Fresh garlic is always the best option, but you can use pre-minced garlic if that’s what you have on hand.
• Kosher Salt and Black Pepper: These seasonings bring out the natural flavors of the vegetables and cheese. You can adjust the salt and pepper to your taste, but don’t overdo it—remember, the goat cheese itself is quite flavorful and will contribute to the overall seasoning of the casserole.
• Green Onions (2, sliced): Green onions provide a fresh, mild onion flavor that enhances the overall dish. Their slight sharpness adds a nice contrast to the richness of the eggs and cheese. They are sprinkled over the vegetable mixture, adding a burst of color and flavor.
• Goat Cheese (4 ounces): Goat cheese is the key to this casserole’s creamy, tangy element. It crumbles beautifully over the vegetables and eggs, adding richness without overwhelming the other ingredients. If you’re not a fan of goat cheese, you can easily substitute it with feta cheese, ricotta, or even a sharp cheddar for a different flavor profile.
• Eggs (18 large): The eggs are the foundation of the casserole, holding everything together in a soft, custard-like texture. They provide the bulk of the dish and make it filling and satisfying. The eggs will set during baking, forming a firm yet tender base for the vegetables and cheese.
• Milk (1/2 cup): A small amount of milk is added to the eggs to make the texture light and fluffy. You can use any type of milk you prefer—whole milk for extra richness, or a plant-based milk like almond or oat milk for a dairy-free version.
• Chives (for garnish, optional): Fresh chives add a delicate, onion-like flavor and a pop of color as a garnish on top of the casserole. If you don’t have chives, parsley or another fresh herb could work just as well.

Step-by-Step Instructions: How to Make This Casserole

Now that we’ve covered the ingredients, let’s walk through the steps to make this delicious breakfast casserole. The process is straightforward and can be done in less than an hour. It’s the perfect recipe to make when you need a hearty meal with minimal effort.

1. Preheat the oven and prepare the baking dish.
   Begin by preheating your oven to 350°F (175°C). While the oven is heating up, grease a 9×13-inch baking dish with nonstick cooking spray to ensure the casserole doesn’t stick during baking. Set the dish aside while you prepare the vegetables.
2. Sauté the mushrooms and spinach.
   Heat a tablespoon of olive oil in a large skillet over medium-high heat. Once the oil is hot, add the sliced cremini mushrooms. Cook them for about 3 minutes, stirring occasionally, until they’re tender and browned. The mushrooms will release moisture as they cook, and their natural savory aroma will begin to fill the kitchen. Add the minced garlic and cook for another minute until it becomes fragrant. Then, add the fresh spinach leaves and cook for 2–3 minutes, until the spinach wilts down. Season the mixture with kosher salt and black pepper to taste. The combination of garlic, mushrooms, and spinach creates a wonderfully aromatic mixture that will be the base of the casserole.
3. Assemble the casserole.
   Once the vegetables are sautéed and ready, pour the mixture into the prepared baking dish. Spread it out evenly to cover the bottom of the dish. Next, sprinkle the sliced green onions over the vegetable mixture, adding a pop of color and a mild onion flavor. Crumble half of the goat cheese over the vegetables, ensuring it’s spread evenly throughout the dish. The creamy goat cheese will melt into the vegetables as it bakes, adding a rich tanginess that complements the other flavors.
4. Prepare the egg mixture.
   In a large bowl, whisk together the eggs and milk until smooth. Season with a pinch of kosher salt and freshly ground black pepper. The egg mixture should be well-blended, and the milk will make it lighter and fluffier. Pour this mixture evenly over the vegetables and cheese in the baking dish. Be sure the egg mixture covers everything completely.
5. Top with more goat cheese.
   Crumble the remaining half of the goat cheese and sprinkle it over the top of the egg mixture. This additional layer of cheese will melt into the casserole as it bakes, creating a deliciously creamy topping.
6. Bake the casserole.
   Place the casserole in the preheated oven and bake for 30–40 minutes, or until the eggs are set and slightly golden around the edges. The top of the casserole should look golden and slightly puffed, and the edges should be firm. If you gently shake the baking dish, the center should be set without wobbling. Once it’s done, remove the casserole from the oven and let it cool for 5 minutes before cutting it into squares.
7. Garnish and serve.
   For an added touch of freshness, garnish the casserole with freshly chopped chives or another herb of your choice. This adds color and an additional burst of flavor. Slice the casserole into squares and serve it warm. It’s perfect on its own, but you can also pair it with a side of crispy bacon, roasted potatoes, or a light salad for a more complete meal.

Tips and Tricks for Success

• Make-Ahead Option: This casserole can be prepared ahead of time. Assemble the casserole the night before, cover it tightly, and store it in the refrigerator. In the morning, simply pop it in the oven and bake as usual. It’s a great option for busy mornings when you want a warm, homemade breakfast without the hassle.
• Vegetarian Variations: If you want to add even more vegetables to the casserole, feel free to experiment. Try adding bell peppers, zucchini, or tomatoes to the mushroom and spinach base. You could also toss in some cooked sweet potatoes or roasted Brussels sprouts for a unique twist.
• Substitute the Cheese: Goat cheese is rich and tangy, but if it’s not to your liking, you can substitute it with feta cheese for a similar crumbly texture and tang. Cheddar cheese or Monterey Jack will also work well if you prefer a more traditional cheese flavor.
• Make It Heartier: For a more substantial casserole, consider adding cooked bacon, sausage, or ham to the vegetable mixture. This will give the dish a savory, meaty richness that pairs perfectly with the vegetables and eggs.

Why This Casserole Should Be Your Go-To Breakfast

The Spinach Mushroom Breakfast Casserole is the ultimate dish for anyone looking to enjoy a hearty, satisfying breakfast or brunch with minimal effort. It’s filled with healthy vegetables, creamy cheese, and fluffy eggs that come together in a single dish, making it easy to serve to a crowd or enjoy as a simple family meal. With its rich flavors, delightful textures, and versatility, it’s bound to become a favorite in your recipe collection.

Whether you’re hosting a brunch party, preparing a weekend breakfast, or meal prepping for busy mornings, this casserole is a reliable, crowd-pleasing dish that’s sure to impress. So grab your ingredients, preheat your oven, and get ready to indulge in the deliciousness of this Spinach Mushroom Breakfast Casserole. Happy cooking!