If you’re looking for a lighter, veggie-packed breakfast option, this spinach and mushroom breakfast casserole is a perfect choice. It’s flavorful, nutritious, and simple to make, offering a balance of protein, fiber, and vitamins. Ideal for brunch gatherings, meal prep, or a healthy family breakfast, this dish delivers comfort without being heavy.

What is Spinach and Mushroom Breakfast Casserole?

This casserole is a baked egg-based dish filled with fresh spinach, mushrooms, cheese, and seasonings. It’s similar to a crustless quiche, making it lower in carbs while still hearty enough to serve as a main breakfast dish.

Easy Spinach and Mushroom Breakfast Casserole recipe

Other Easy Breakfast Casserole Recipes

Reasons to Try Spinach and Mushroom Breakfast Casserole

Vegetarian-friendly – A hearty dish without meat.
Nutritious and filling – Packed with protein, fiber, and vitamins.
Low-carb option – Works for keto and gluten-free diets.
Meal prep ready – Stores well for quick weekday breakfasts.
Versatile recipe – Easily customizable with other vegetables or cheeses.

Ingredients Needed to Make Spinach and Mushroom Breakfast Casserole

8 large eggs
1 cup milk (or unsweetened almond milk for a lighter option)
2 cups fresh spinach, chopped
2 cups mushrooms, sliced
1 small onion, finely chopped (optional)
2 cups shredded cheese (cheddar, mozzarella, or Swiss)
1 tablespoon olive oil (for sautéing)
1 teaspoon garlic powder
1 teaspoon salt
½ teaspoon black pepper
2 tablespoons fresh parsley, chopped (optional garnish)

Instructions to Prepare Spinach and Mushroom Breakfast Casserole

Step 1: Preheat the oven

Set oven to 350°F (175°C) and grease a 9×13-inch baking dish.

Step 2: Sauté vegetables

In a skillet, heat olive oil. Add onion (if using) and cook until soft. Add mushrooms and cook until golden and their moisture evaporates. Stir in spinach and cook until just wilted.

Step 3: Mix egg base

In a large bowl, whisk eggs, milk, garlic powder, salt, and pepper until smooth.

Step 4: Assemble casserole

Spread the spinach and mushroom mixture evenly in the baking dish. Pour egg mixture over the vegetables. Sprinkle shredded cheese evenly on top.

Step 5: Bake casserole

Bake uncovered for 35–40 minutes, or until the eggs are set and the top is lightly golden.

Step 6: Rest and serve

Allow casserole to cool for 5 minutes before slicing. Garnish with parsley.

What Goes Well With Spinach and Mushroom Breakfast Casserole

Fresh fruit salad – Balances savory flavors with natural sweetness.
Whole-grain toast – Perfect for pairing with the fluffy eggs.
Avocado slices – Creamy and nutrient-rich addition.
Roasted potatoes – For a more filling breakfast.
Herbal tea or coffee – Classic breakfast pairings.

Key Tips for Making Spinach and Mushroom Breakfast Casserole

Drain mushrooms well – Cook until their liquid evaporates to avoid a watery casserole.
Use fresh spinach – Adds better flavor and texture than frozen.
Whisk eggs thoroughly – Ensures an even, fluffy texture.
Add cheese in layers – Enhances flavor throughout.
Bake uncovered – Helps the top brown slightly.
Let it rest before slicing – Keeps the casserole intact.

Creative Variations of Spinach and Mushroom Breakfast Casserole

Add feta cheese – For a Mediterranean flavor.
Make it spicy – Add jalapeños or crushed red pepper.
Add more veggies – Include zucchini, bell peppers, or broccoli.
Protein boost – Mix in turkey sausage or chicken.
Dairy-free version – Use plant-based milk and dairy-free cheese.

Storage Guidelines for Spinach and Mushroom Breakfast Casserole

Refrigerate leftovers – Store covered in the fridge for up to 4 days.
Freeze portions – Wrap tightly and freeze for up to 2 months.
Cool completely – Prevents condensation when storing.
Portion before freezing – Makes reheating quicker.

Reheating Tips for Spinach and Mushroom Breakfast Casserole

Oven method – Warm at 325°F (160°C) for 15 minutes.
Microwave option – Heat slices on medium power for 2–3 minutes.
From frozen – Bake covered at 350°F (175°C) for 40–45 minutes.

Nutrition Value (per serving):

Calories: ~280
Protein: 19g
Carbohydrates: 6g
Fat: 20g
Fiber: 2g
Sodium: 620mg

FAQs

Do you cook mushrooms before adding them to a breakfast casserole?

Yes, mushrooms should be sautéed before adding to the casserole. Cooking them removes excess moisture and enhances their flavor, preventing the dish from becoming watery.

Can I use frozen spinach in a spinach and mushroom breakfast casserole?

Yes, frozen spinach can be used, but it should be thawed and squeezed dry to remove as much liquid as possible. This ensures the casserole sets properly.

How do you keep a spinach and mushroom casserole from being watery?

To avoid a watery casserole, cook mushrooms until their liquid evaporates, and drain spinach thoroughly before adding. Also, let the casserole rest for 5–10 minutes after baking so the eggs can firm up.

Can I make spinach and mushroom breakfast casserole ahead of time?

Yes, you can prepare it the night before, cover it, and refrigerate it. Bake in the morning, adding about 5–10 minutes to the cooking time since it will start cold.

Final Words

This spinach and mushroom breakfast casserole is a wholesome, versatile dish that’s just as delicious for brunch as it is for weekly meal prep. With its fluffy eggs, melted cheese, and earthy vegetables, it’s a satisfying meal that brings both comfort and nutrition to your mornings.