Servings: 6–8
Prep time: 20 minutes
Cook time: 35–45 minutes
Total: about 1 hour
Oven: 350°F / 175°C
Dish: 9–10 inch round glass baking dish, about 2–2½ inches deep
Ingredients
Egg mixture
8 large eggs
½ cup whole milk, half-and-half, or unsweetened milk of choice
½ teaspoon salt
½ teaspoon black pepper
½ teaspoon garlic powder
½ teaspoon Italian seasoning
¼ teaspoon paprika
¼ teaspoon dried thyme
Vegetables
2 cups fresh spinach, roughly chopped
1½ cups mushrooms, sliced
1 medium red bell pepper, diced
½ medium onion, finely diced
2 cloves garlic, minced
1 tablespoon olive oil
½ cup cherry tomatoes, chopped or 1 small tomato, diced
¼ cup chopped fresh parsley, optional
Cheese
¾ cup shredded cheddar cheese
¼ cup shredded mozzarella
2 tablespoons grated Parmesan, optional
For a lighter version, use reduced-fat cheese. For a dairy-free version, use an unsweetened plant milk and dairy-free shredded cheese.
Full Step-by-Step Recipe
1. Prepare the oven and dish
Preheat your oven to 350°F (175°C).
Lightly grease a 9–10-inch round glass baking dish with olive oil or cooking spray.
If your dish is particularly shallow, use a slightly larger dish so the egg mixture doesn’t overflow.
2. Cook the mushrooms
Heat 1 tablespoon olive oil in a large skillet over medium-high heat.
Add the sliced mushrooms.
Cook for approximately 5–7 minutes, stirring occasionally, until the mushrooms release their moisture and begin to brown.
Important: Don’t rush this step. Excess mushroom water can make the finished frittata watery.
3. Add onion and bell pepper
Add:
diced onion
red bell pepper
Cook for another 4–5 minutes, until the onion softens and the pepper becomes slightly tender.
4. Add garlic
Add the minced garlic.
Cook for about 30–60 seconds, just until fragrant.
Don’t let the garlic become dark brown.
5. Add spinach
Add the chopped spinach in handfuls.
Cook for approximately 1–2 minutes, stirring, until it wilts.
If there is a lot of liquid in the pan, continue cooking until most of it evaporates.
Established frittata recipes similarly recommend wilting spinach and removing excess moisture before combining it with the eggs.
M
Mayo Clinic
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6. Add tomatoes
Turn off the heat.
Stir in the chopped tomatoes and parsley.
Allow the vegetables to cool for about 5 minutes.
This prevents the hot vegetables from partially cooking the eggs when they’re combined.
7. Make the egg mixture
In a large bowl, whisk together:
8 eggs
½ cup milk
salt
black pepper
garlic powder
Italian seasoning
paprika
thyme
Whisk until the eggs are completely combined and slightly foamy.
8. Add cheese
Stir about ½ cup of the cheddar and all of the mozzarella into the egg mixture.
Reserve the remaining cheddar and Parmesan for the top.
9. Combine everything
Add the cooked vegetables to the egg mixture.
Stir gently until the vegetables are evenly distributed.
10. Fill the baking dish
Pour the mixture into your greased round glass baking dish.
Spread everything evenly.
Sprinkle the remaining cheddar and Parmesan over the surface.
11. Bake
Place the dish on the middle rack.
Bake at 350°F / 175°C for approximately 35–45 minutes.
The exact time depends on the depth of your dish.
Start checking at about 30 minutes.
The frittata is ready when:
the center is set
the top is lightly golden
the edges are slightly puffed
the center doesn’t look liquid when gently shaken
For food safety, the USDA vegetable-frittata recipe specifies heating the egg dish to 165°F (74°C) or higher for at least 15 seconds.
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12. Rest before cutting
Remove from the oven and let it rest for 8–10 minutes.
This is important. The eggs continue to set while cooling and the slices will hold together better.
Cut into 6–8 wedges and serve.
Approximate Nutrition
Because the exact nutrition changes with the size of the eggs, type of milk, amount/type of cheese, and vegetables, these numbers are estimates rather than laboratory measurements.
For the recipe as written, assuming 8 servings:
Nutrient Approx. per serving
Calories 225–240 kcal
Protein 15–17 g
Total fat 15–17 g
Saturated fat 5–6 g
Carbohydrates 7–9 g
Dietary fiber 2 g
Total sugars 3–4 g
Added sugars 0 g
Cholesterol ~190–210 mg
Sodium ~400–500 mg
Potassium ~400–500 mg
Calcium ~180–220 mg
Iron ~2–3 mg
Vitamin A High
Vitamin C High
Vitamin D Moderate
Vitamin B12 Moderate–high
For comparison, a USDA vegetable frittata containing mushrooms, onions, red pepper, spinach, cheese, milk and eggs provides protein, fiber, vitamin A, vitamin C, calcium, iron and potassium.
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A spinach-and-red-pepper frittata from the U.S. Department of Veterans Affairs provides another useful comparison: its ¼-recipe serving contains about 225 calories, 17.5 g protein, 15 g fat, 6 g carbohydrate and 2 g fiber.
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Nutrition.va
To reduce calories
Use:
6 whole eggs + 4 egg whites
skim milk
½ cup reduced-fat cheese
2 teaspoons olive oil
To increase protein
Use:
8 eggs
½ cup egg whites
¾ cup cottage cheese blended into the egg mixture
¾ cup cheese
You can also add cooked chicken or turkey.
To make it low-carb
The recipe is already relatively low in carbohydrates. Leave out:
potatoes
bread
flour
and increase the spinach, mushrooms and peppers.
To make it vegetarian
The recipe as written is vegetarian.
To make it gluten-free
The recipe contains no wheat or flour. Just check that any packaged cheese/seasonings you use are certified gluten-free if cross-contact is a concern. Mayo Clinic also lists its comparable spinach-mushroom frittata as gluten-free.
M
Mayo Clinic
⭐ Secrets for Getting the Same Look as the Photo
1. Remove vegetable moisture.
This is the biggest secret. Mushrooms and spinach contain a lot of water. Cook them until the excess liquid has evaporated.
2. Don’t overbeat the eggs.
Whisk enough to combine them, but there’s no need to whip them aggressively.
3. Use plenty of vegetables.
The colorful pieces visible in the photo come from spinach, red pepper, mushrooms and onion.
4. Use a glass dish.
A round glass casserole dish gives the thick, deep appearance shown in the photograph.
5. Don’t overbake.
Overbaking makes eggs rubbery and can cause liquid to separate from the vegetables.
6. Let it rest.
Give it 8–10 minutes before cutting.
7. For a more golden top:
During the final 2–3 minutes, you can move the dish to a higher oven rack, watching carefully so the cheese doesn’t burn.
Recipe Q&A
Can I use frozen spinach?
Yes. Thaw approximately 10 oz / 280 g frozen spinach, then squeeze it very thoroughly to remove excess water. This is especially important for a baked egg casserole.
Can I use fresh spinach?
Absolutely. Use about 2–3 cups fresh spinach. Cook it until wilted and allow excess water to evaporate.
Why is my frittata watery?
Usually one of three things happened:
The spinach wasn’t squeezed/drained.
The mushrooms weren’t cooked long enough.
The frittata was cut immediately after coming out of the oven.
Cook the vegetables until their excess moisture is gone and let the finished frittata rest.
Can I prepare it the night before?
Yes. Cook the vegetables, cool them, and refrigerate them. The next day, combine with the egg mixture and bake.
A comparable mushroom-spinach baked egg recipe also allows the vegetable mixture to be prepared ahead and refrigerated overnight.
F
Food Network
Can I add potatoes?
Yes. Add approximately 1 cup cooked diced potato.
Don’t use raw potatoes unless you cook them first because they may remain hard while the eggs finish cooking.
Can I add broccoli?
Yes. Use about 1 cup finely chopped cooked broccoli.
Can I add chicken?
Yes. Add 1–1½ cups cooked diced chicken for a higher-protein meal.
Can I add bacon?
Yes. Add about 4 strips cooked and crumbled bacon, but reduce the added salt because bacon and cheese are already salty.
What other vegetables work?
Good choices include:
zucchini
broccoli
asparagus
kale
green bell pepper
yellow pepper
tomatoes
roasted red pepper
cooked potatoes
corn
Always cook high-moisture vegetables first.
Can I use feta instead of cheddar?
Definitely. Feta gives it a Mediterranean flavor. About ½–¾ cup crumbled feta works well.
Can I make it without cheese?
Yes. Simply omit the cheese. Add a little more seasoning, herbs, or nutritional yeast if desired.
Can I use plant milk?
Yes. Use ½ cup unsweetened almond, soy, oat, or other suitable milk. Unsweetened soy milk is particularly good because it adds some protein.
Why did my frittata puff up and then collapse?
That’s normal.
Eggs expand as they heat, then lose some of that volume as they cool. A small amount of settling is expected.
How do I know when it’s done?
The center should be set rather than liquid or visibly sloshing. For the safest result, use an instant-read thermometer and make sure the center reaches 165°F / 74°C.
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How long does it keep?
Refrigerate leftovers promptly in a covered container.
For best quality, eat within 3–4 days.
Can I freeze it?
Yes. Cool completely, cut into individual portions, wrap well, and freeze.
Thaw overnight in the refrigerator and reheat until hot throughout. The texture can be slightly softer after freezing because of the vegetables.
How do I reheat it?
Microwave: 45–90 seconds per portion, depending on your microwave.
Oven: 325°F / 165°C for about 10–15 minutes.
Cover loosely with foil if reheating several portions so the top doesn’t dry out.
Serving Ideas
This frittata works particularly well for:
breakfast
brunch
lunch
light dinner
meal prep
vegetarian family meals
Serve it with:
Fresh: green salad, sliced avocado, tomatoes, cucumber
Carbohydrates: whole-grain toast, roasted potatoes, sourdough
Sauces: salsa, hot sauce, pesto, tzatziki
Breakfast: fresh fruit and coffee/tea
Dinner: salad + roasted vegetables
Flavor Variations
Mediterranean
Use spinach + mushrooms + red pepper + feta + oregano + parsley.
Mexican-style
Use peppers + corn + black beans + cheddar + cilantro + cumin, then serve with salsa.
Italian-style
Use spinach + mushrooms + sun-dried tomatoes + mozzarella + Parmesan + basil.
High-protein
Add chicken, turkey, cottage cheese, or additional egg whites.
Very vegetable-heavy
Increase the spinach, mushrooms and peppers while reducing the cheese.
Bottom line: for the closest result to your photograph, use 8 eggs, spinach, mushrooms, red bell pepper, onion, garlic, cheddar/mozzarella, and herbs in a deep round glass dish, and concentrate on cooking the vegetables until their excess moisture is gone before combining them with the eggs. That will give you the colorful, thick, golden, sliceable
With years of experience in restaurant research and local SEO, Sara creates accurate, user-friendly guides that work for both people and search engines. Her goal is to help users go from search results to their nearest restaurant or menu choice with as few clicks as possible.
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