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Whether you’re hosting a Brunch Potluck or just need a hearty formula for those chilly mornings, this Spinach & Mushroom Egg Casserole hits all the right notes. I first whipped it up on a sleepy Saturday after realizing my Breakfast Basket was basically empty—again. Sound familiar? 🙂 This breakfast casserole blends fresh spinach, juicy mushrooms, and fluffy eggs into one glorious bake. Ever wrestled with a box of Mini Quiche Recipes or tried juggling an Egg Frittata only to end up with soggy sides? Me too. That’s why I merged all my favorite elements—think Tortilla Quiche Bake meets a classic Egg Casserole Recipe—and made magic.
This dish nails Breakfast Ideas For A Crowd: it serves a dozen without breaking a sweat. Plus, it doubles as a Healthy Breakfast Casserole that helps when you’re counting macros or just faking it till you make it. It’s perfect for Breakfast Casserole Make Ahead sessions and works as an Overnight Breakfast Casserole With Hashbrowns if you sneak in some spuds. I mean, who doesn’t love a breakfast that practically cooks itself? IMO, this ranks at the top of my Breakfast Casserole Recipes list—no judgment if you snag a second slice before anyone notices. Ready to ditch boring cereal for something epic?
Ingredients
- 8 large eggs
- 1 cup milk (whole or 2%)
- 2 cups fresh spinach, chopped
- 1 cup mushrooms, sliced
- 1 cup shredded cheddar cheese
- ½ cup diced onion
- 2 cloves garlic, minced
- 1 tsp salt
- ½ tsp black pepper
- ¼ tsp red pepper flakes (optional)
- 2 tbsp olive oil or butter
- Optional: 2 cups cubed day-old bread or hashbrowns (for a heartier bite)
Instructions
- Preheat your oven to 375°F (190°C). Grab a 9×13-inch baking dish, spray it with nonstick spray, or rub it with butter. This little step makes cleanup way easier—trust me, I’ve been there.
- Sauté the veggies. Heat olive oil in a skillet over medium heat. Toss in mushrooms and onions, stirring until they soften (about 4–5 minutes). Add garlic and spinach, cook another 2 minutes until wilted. FYI, this builds flavor that a lazy overnight bake just can’t match.
- Whisk the eggs and milk. In a large bowl, beat eggs with milk, salt, pepper, and red pepper flakes. I like to pretend I’m a culinary wizard, but honestly it’s just vigorous whisking. 😉
- Combine everything. Stir in the sautéed vegetables and cheese (reserve a handful for topping). If you opted for bread cubes or hashbrowns, fold them in now. This is your chance to swap in other veggies or meats—more on that in Variations.
- Pour into the dish. Spread the mixture evenly in your prepared pan. Sprinkle the remaining cheese on top to get that golden, bubbly crust we all drool over.
- Bake for 30–35 minutes. Stick a knife or toothpick in the center—it should come out clean with a few moist crumbs. Patience is key, but who am I kidding? Sneak a peek if you must.
- Let it rest. Remove from oven and let the casserole sit for about 5 minutes. This helps it set so you can slice perfect squares without turning it into a soggy mess.
- Serve and enjoy! Slice into squares, plate it up, and watch everyone fight over the last piece. Pro tip: garnish with fresh herbs or a dollop of Greek yogurt for a tangy kick.
Variations
If you love playing chef, you’ll adore these Breakfast Casserole Ideas:
- Meaty Twist: Swap half the spinach for cooked sausage or crumbled bacon. You’ll feel like a breakfast hero at your next Brunch Casserole.
- Veggie Deluxe: Add bell peppers, zucchini ribbons, or cherry tomatoes. This ups the color and nutrients, making it a legit Healthy Breakfast Casserole.
- Cheesy Fiesta: Stir in pepper jack or feta for a spicy, tangy bite. Serve with salsa and avocado—instant Savory Breakfast flair.
Serving & Tips
This breakfast casserole shines on its own but also pairs beautifully with: a bowl of fresh fruit, a side of crispy hashbrowns, or even a loaf of crusty bread. If you’re planning ahead, wrap individual slices in parchment and refrigerate—perfect for grabbing on busy mornings. You can also freeze portions in airtight containers for up to 2 months. Reheat at 350°F for 10–12 minutes, or zap in the microwave for 1–2 minutes if you’re in a major rush. Pro tip: let it come to room temperature before reheating to keep it from drying out.
Looking to jazz up your brunch spread? Scatter some microgreens on top, serve with a zesty chimichurri, or set up a DIY topping station (think hot sauce, sour cream, chopped herbs). This recipe fits right into any Breakfast Ideas For A Crowd lineup—no judgement if you end up eating half the pan solo. 🙂
Final Thoughts
I love how this Spinach & Mushroom Egg Casserole feels fancy yet takes minutes to prep. It’s my go-to for weekend brunches, Brunch Potluck gatherings, and those rushed mornings when cereal just won’t cut it. Even my pickiest eaters give it two thumbs up—no small feat, IMO. Whether you stick to the classic recipe or riff on it, you’ll end up with a dish that’s satisfying, comforting, and easy to customize.
So next time you’re hunting for Easy Breakfast Ideas or craving a crowd-pleaser without the stress, remember this recipe. It’s proof that a little planning (or an overnight soak) can lead to big flavor. Not all heroes wear capes—some just serve up a killer breakfast casserole. Enjoy!
Spinach & Mushroom Egg Casserole
Ingredients
Equipment
Method
- Preheat oven to 375°F (190°C). Grease a 9×13-inch baking dish with nonstick spray or butter.
- In a skillet, heat olive oil over medium heat. Add mushrooms and onions, cook until softened (4–5 minutes). Add garlic and spinach, cook 2 more minutes until wilted.
- In a large bowl, whisk eggs, milk, salt, pepper, and red pepper flakes until well combined.
- Stir in sautéed vegetables and most of the shredded cheese. Fold in bread cubes or hashbrowns if using.
- Pour mixture into baking dish. Top with remaining cheese.
- Bake for 30–35 minutes or until center is set and top is golden. A knife inserted in the center should come out clean.
- Let rest 5–10 minutes before slicing. Serve warm and enjoy!
Nutrition
Notes
Tried this recipe?
Let us know how it was!FAQs
Can I make this casserole ahead of time?
Absolutely! For a true Breakfast Casserole Make Ahead, assemble the dish, cover it tightly, and refrigerate overnight. In the morning, just pop it in the oven for the full bake time plus a few extra minutes.
Can I freeze and reheat leftovers?
You bet. Cut leftovers into individual portions, wrap them in foil or plastic wrap, and freeze up to 2 months. To reheat, thaw overnight in the fridge, then warm at 350°F for 10–12 minutes or microwave for about 2 minutes.
What can I substitute for spinach?
If you’re not a spinach fan, swap in kale, Swiss chard, or even broccoli florets. You can also toss in frozen spinach—just squeeze out excess water before mixing, so your casserole doesn’t turn soggy.
Is this recipe vegetarian or can I add meat?
It’s vegetarian by default, but you can easily add cooked sausage, bacon bits, or diced ham for extra protein. For a vegan tweak, use a plant-based egg substitute and vegan cheese—though results may vary in texture.
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