If you’re looking for a super simple, cozy breakfast (or brunch!) that the whole family will love, this Mushroom and Egg Casserole is it!
It’s hearty, flavorful, and packed with protein. The best part? You can prep it ahead of time, making busy mornings so much easier.
I’ve made this for holiday mornings, lazy Sundays, and even weeknight dinners—it’s always a hit.
The mushrooms give it an earthy flavor, and the eggs make it so fluffy and satisfying. Trust me, this one’s going to be a regular in your kitchen!
What You’ll Need
Ingredients:
- 8 large eggs
- 1 cup milk (whole milk or 2%)
- 1 cup shredded cheese (cheddar or mozzarella work great)
- 1 cup sliced mushrooms (white or cremini)
- 1/2 cup diced onions (yellow or white)
- 1/2 cup diced bell peppers (any color)
- 1 teaspoon garlic powder
- 1 teaspoon salt
- 1/2 teaspoon black pepper
- 1 tablespoon olive oil or butter
- 2 tablespoons chopped fresh parsley (optional, for garnish)
Tools:
- 9×13-inch baking dish
- Large mixing bowl
- Whisk
- Cutting board
- Knife
- Skillet
Pro Tips
- Sauté the veggies first – This helps bring out their flavors and ensures they don’t release too much water into the casserole.
- Use fresh mushrooms – Fresh mushrooms add so much more flavor than canned! Cremini mushrooms are a great choice for a richer taste.
- Don’t overmix the eggs – Just whisk until combined; too much air can make the casserole dense.
- Add some spice – A pinch of red pepper flakes or a dash of hot sauce can give this dish a little kick if your family likes it.
- Make it kid-friendly – If your kids aren’t fans of mushrooms, swap them out for more bell peppers or even chopped cooked bacon!
Substitutions and Variations
- Dairy-free: Use almond milk or oat milk and dairy-free cheese.
- Vegetarian-friendly: It already is, but you could toss in more veggies like spinach or zucchini.
- Meaty version: Add cooked sausage, bacon, or ham to make it extra hearty.
- Gluten-free: This dish is naturally gluten-free!
Make Ahead Tips
You can prepare the casserole the night before! Assemble everything in the baking dish, cover tightly with foil or plastic wrap, and store it in the fridge overnight. In the morning, just pop it in the oven and bake as directed.
Instructions
1. Preheat the Oven
Preheat your oven to 375°F (190°C).
2. Sauté the Vegetables
Heat the olive oil in a skillet over medium heat. Add the sliced mushrooms, diced onions, and diced bell peppers. Cook for 5-7 minutes until softened and fragrant.
3. Whisk the Eggs and Milk
In a large mixing bowl, whisk together the eggs, milk, garlic powder, salt, and black pepper until well combined.
4. Combine Everything
Add the sautéed vegetables and half of the shredded cheese to the egg mixture. Stir gently to combine, then pour into a greased 9×13-inch baking dish. Top with the remaining cheese.
5. Bake the Casserole
Place the baking dish in the oven and bake for 30-35 minutes, or until the eggs are set and the top is golden brown.
6. Garnish and Serve
Remove the casserole from the oven, let it cool for 5 minutes, then sprinkle with fresh parsley. Slice into squares and serve warm.
Leftovers and Storage
Leftovers can be stored in an airtight container in the fridge for up to 3 days. Reheat in the microwave for a quick and easy breakfast. You can also freeze individual portions for up to 2 months—just thaw overnight in the fridge and reheat!
Conclusion
This Mushroom and Egg Casserole is one of those recipes you’ll find yourself making again and again. It’s easy, delicious, and perfect for feeding a hungry family. If you give it a try, let me know how it turns out! I’d love to hear your tweaks or answer any questions you have. Leave a comment below—I can’t wait to connect!