Mushroom, Spinach and Mozzarella Frittata
A tender baked egg frittata folded with buttery sautéed mushrooms, garlicky wilted spinach, and pockets of melted mozzarella.
Why You'll Love This Recipe
A hot, filling breakfast with no pile of morning dishes and very little hands-on time. Eggs, mushrooms, spinach, and a little cheese are humble enough, but the sautéing and baking give the dish the tender, custard-soft texture of something more special. Because it bakes in one pan and slices into wedges, it suits both a quiet weekday and a table full of people, and it reheats beautifully for grab-and-go mornings.
The mushrooms have to give up their water first. Cooking them in butter and olive oil until their liquid releases and evaporates concentrates their flavor and, just as importantly, keeps that moisture out of the eggs. A watery frittata is almost always the result of vegetables that went in wet. Wilting the spinach in the same pan and cooking off its liquid does the same job. Whisking the eggs thoroughly incorporates air for a lighter set, and finishing in a moderate oven cooks the custard gently and evenly instead of toughening it over direct heat.
The eggs, the mushrooms, and the spinach all count. The eggs bring complete protein that helps you feel full through the morning, the mushrooms and spinach add earthy depth and plant nutrients, and the mozzarella melts into savory, stretchy pockets that make each bite feel indulgent. A wedge also holds its shape cold, which is worth knowing on the mornings there is no time to warm anything, and it will sit in the refrigerator for three days without losing much. It is filling and satisfying, so it settles the appetite and keeps you comfortable through the morning.
Ingredients
- 8 large eggs
- 2 1/2 cups sliced mushrooms
- 3 cups spinach
- 3/4 cup shredded mozzarella
- 2 tbsp butter
- 1 tbsp olive oil
- 2 cloves garlic, minced
- 1/4 tsp salt
Instructions
- Preheat and prep: Preheat the oven to 375°F (190°C). Wipe the mushrooms clean with a damp paper towel and slice them thin. Peel and finely mince the garlic. If the spinach is in large leaves, give it a rough chop so it wilts evenly.
- Sauté the mushrooms: Set an oven-safe skillet (cast iron or an ovenproof nonstick pan works well) over medium heat. Add the butter and olive oil. Once the butter has melted and stopped foaming, add the sliced mushrooms in an even layer. Cook, stirring occasionally, for 6 to 7 minutes, until they release their liquid, that moisture cooks off, and the edges turn golden brown.
- Wilt the spinach: Add the minced garlic and cook for about 30 seconds, until fragrant but not browned. Add the spinach a handful at a time, stirring, and cook for about 2 minutes until it collapses and any watery liquid has cooked away. Spread the vegetables into an even layer across the bottom of the skillet.
- Add the eggs and cheese: Crack the eggs into a bowl, add the salt, and whisk until the yolks and whites are fully blended and slightly frothy. Pour the eggs evenly over the vegetables in the skillet and let them settle for a few seconds so they run into the gaps. Sprinkle the shredded mozzarella over the top.
- Bake and slice: Carefully transfer the skillet to the oven and bake for 14 to 16 minutes, until the center is set and no longer jiggles when you gently shake the pan and the top is lightly golden. Let it rest for a few minutes, then slice into wedges and serve.
Variations
- Cheese swap: Trade the mozzarella for shredded provolone, fontina, or a sharp aged cheese for a bolder, tangier finish. All of these keep the dish rich and add dairy just as the mozzarella does.
- Add a savory meat: Brown some crumbled Italian sausage or diced bacon before the mushrooms and drain off the excess fat. This adds meat and deepens the savory flavor without changing the tender egg base.
- Fresh herbs: Whisk chopped fresh basil, chives, or parsley into the eggs, or scatter them over the finished frittata. Herbs brighten the earthy mushrooms and add color with no meaningful carbs.
- A little heat: Add a pinch of red pepper flakes with the garlic, or fold in chopped roasted red peppers for a gentle sweetness and warmth that plays well against the mozzarella.
- Green onion and extra vegetables: Stir in sliced green onions, diced bell pepper, or halved cherry tomatoes with the spinach. Cook off any extra moisture first so the eggs still set cleanly.
Storage & Leftovers
Cool leftover wedges to room temperature, then store them in an airtight container in the refrigerator for up to 4 days. Keeping the pieces in a single layer, or separated by parchment, stops them from steaming and going soggy against one another.
To reheat, warm a wedge in a 325°F (163°C) oven or toaster oven for about 8 to 10 minutes until heated through. This keeps the texture tender and the top from turning rubbery. A microwave works in a pinch: use short bursts at reduced power so the eggs warm gently rather than overcooking and weeping.
For make-ahead mornings, bake the whole frittata a day or two in advance and refrigerate it whole or pre-sliced. It is excellent cold or at room temperature straight from the fridge, which makes it easy to pack for a fast breakfast or a slice with an afternoon coffee.
Notes & Tips
- Cook the mushrooms dry: Do not rush the mushrooms. Wait until the liquid they release has fully evaporated and the edges brown. This is the single biggest step to preventing a watery frittata.
- Use an oven-safe pan: Make sure your skillet has no plastic handle before it goes in the oven. If your only pan is not ovenproof, transfer the sautéed vegetables and eggs to a buttered baking dish before adding the cheese and baking.
- Grate your own cheese: Shred mozzarella from a block if you can. Pre-shredded cheese is coated with anti-caking starch that can keep it from melting into those smooth, stretchy pockets.
- Know when it is set: The frittata is done when the center no longer jiggles as a liquid when you gently shake the pan and a knife slipped into the middle comes out clean. Pull it before the top browns heavily to keep the eggs tender.
- Salt with a light hand: The cheese already brings salt, so taste before adding more. If you are serving it alongside anything cured or briny, you may want even less in the eggs.
- Serve it well: A simple green salad with a lemony vinaigrette or a few slices of ripe avocado rounds this out into a full meal without weighing it down.
Nutrition & Mindful Eating
- The mushrooms, the spinach and the eggs need each other here. The mushrooms bring the savory depth, the spinach brings color and a soft mineral edge, and the eggs hold both in a tender set that slices clean.
- Mushrooms cooked hard in butter until their water leaves and the edges go dark are what make this taste like more than eggs, and they carry selenium, potassium and B vitamins in with all that browning.
- Eggs pulled from the heat before they tighten stay custardy through the middle, which is the whole point of a frittata, and each one brings complete protein and the choline concentrated in the yolk.
- Mozzarella laid over the top melts into soft white pools and browns lightly at the surface, and the garlic that went into the pan with the mushrooms comes through underneath it in every wedge.
- Spinach folded in off the heat keeps its folate and vitamin K close to intact, and a wedge of this, dense with egg and rich with butter and olive oil, eats like a proper sit-down breakfast.
- As you eat, watch the cheese stretch off the wedge and taste for the garlic sitting under the mushrooms, and let a slower fork give you time to notice when you are content.
Frequently Asked Questions
Why did my frittata turn out watery?
Almost always it is moisture from the vegetables. Cook the mushrooms until their released liquid has fully evaporated and they begin to brown, and wilt the spinach until its water has cooked off, before the eggs go in. Frozen spinach especially needs to be thawed and squeezed very dry.
Can I use frozen spinach instead of fresh?
Yes. Thaw it completely and squeeze out as much water as you can with your hands or a clean towel, then add it with the garlic to warm through. Skip the wilting time since it is already soft.
My skillet handle is plastic. How do I bake this?
Sauté the vegetables in your regular pan, then spread them in a buttered baking dish, pour the whisked eggs over, top with the cheese, and bake as directed. Any shallow oven-safe dish works.
Can I make it ahead and eat it cold?
Absolutely. This frittata holds up well for several days in the refrigerator and tastes great cold or at room temperature, which makes it a reliable make-ahead breakfast you can slice and grab all week.