Crustless Spinach, Mushroom & Red Pepper Quiche

Serves: 6
Prep: 20 minutes
Cook: 40–50 minutes
Total: about 1 hour
Dish: 9-inch / 23-cm pie or round baking dish

Ingredients

Vegetables

8 oz (225 g) mushrooms, finely sliced
4 cups (about 120–140 g) fresh spinach
½ medium red bell pepper, finely diced
½ small onion, finely diced
2 cloves garlic, minced
1 tbsp olive oil

Egg mixture

6 large eggs
½ cup (120 ml) milk
½ cup (50–60 g) shredded mozzarella
¼ cup (25 g) grated Parmesan
¼ cup (40–50 g) crumbled feta, optional
½ tsp salt
¼ tsp black pepper
¼ tsp dried oregano
Pinch of nutmeg
Optional: ¼ tsp red-chili flakes

The combination of spinach, mushrooms, eggs, milk and cheese is consistent with established crustless-quiche recipes; one University of Illinois Extension version, for example, uses spinach, mushrooms, feta, Parmesan, mozzarella, eggs and milk and bakes at 350°F.

Method
Heat the oven to 350°F (175–180°C). Lightly grease a 9-inch round baking dish.
Cook the mushrooms.
Heat olive oil in a large skillet over medium-high heat. Add mushrooms and cook for 5–7 minutes, stirring occasionally, until browned and most of their moisture has evaporated.
Add onion and pepper.
Cook for another 3–4 minutes, then add garlic and cook for 30 seconds.
Add spinach.
Add the spinach in handfuls and cook just until wilted, about 2–3 minutes.
Remove excess moisture.
This is important. Let the vegetables cool slightly, then squeeze or press out excess liquid. Excess water is one of the main reasons crustless quiche becomes watery.
Prepare the custard.
Whisk eggs, milk, salt, pepper, oregano and nutmeg until well combined.
Add cheese.
Stir the mozzarella and Parmesan into the egg mixture. Reserve a little cheese for the top if desired.
Assemble.
Spread the cooked vegetables evenly in the baking dish. Pour the egg mixture over them. Sprinkle feta and remaining cheese on top.
Bake.
Bake for 40–50 minutes, until the center is set and the surface is golden. A tested spinach-mushroom recipe recommends baking until the eggs are set and the top begins to brown.
Rest before cutting.
Allow it to stand for 10–15 minutes. For especially clean slices, allow it to cool longer; the center continues firming as it rests. Similar recipes recommend resting before serving.
⭐ Tips for the texture shown in the photo
Don’t skip squeezing the spinach.
Brown the mushrooms well rather than simply steaming them.
Don’t overbake—the quiche should be firm but tender, not rubbery.
For a richer, creamier result, replace half the milk with heavy cream.
For a lighter version, use skim or 2% milk and part-skim mozzarella.
Feta gives a salty, tangy flavor; Gruyère or cheddar works well too.
You can add broccoli, zucchini, tomatoes, asparagus or cooked chicken, keeping the total vegetable/meat additions moderate so the egg mixture still sets properly.
Nut information & allergens

This recipe is naturally nut-free as written.

There are no peanuts, almonds, walnuts, cashews, pistachios, pecans or other tree nuts in the ingredients.

However:

Egg: contains egg.
Milk/dairy: mozzarella, Parmesan, feta and milk contain dairy.
Gluten: the recipe is crustless and naturally gluten-free, provided all packaged ingredients are certified gluten-free if required.
Nuts: none intentionally added.
Cross-contact: if this is being prepared for someone with a serious nut allergy, check cheese, milk and spice labels and use products from a facility appropriate for that allergy.
Approximate nutrition

For 1 of 6 servings, using the ingredients above:

Nutrient Approx. amount
Calories 230–280 kcal
Protein 17–20 g
Carbohydrates 7–10 g
Fiber 1–2 g
Fat 15–19 g
Saturated fat 6–8 g
Sodium 400–600 mg

The exact numbers vary considerably with the type and quantity of cheese and milk. For comparison, a University of Illinois Extension spinach-mushroom-feta quiche provides 130 calories, 11 g protein, 7 g carbohydrate and 5 g fat per serving, while another spinach-mushroom version lists about 283 calories and 20 g protein per serving.

Q&A

Q: Is this a quiche or a frittata?
A: It is best described as a crustless quiche because it has an egg-and-milk custard. A frittata generally has a firmer, more egg-forward texture.

Q: Can I make it without cheese?
A: Yes. Replace the cheese with additional vegetables and seasonings. The texture will be somewhat lighter and less creamy.

Q: Can I use frozen spinach?
A: Absolutely. Thaw it completely and squeeze it very dry before adding it.

Q: Why did my quiche become watery?
A: Usually because the spinach, mushrooms or other vegetables released too much water. Brown the mushrooms thoroughly and squeeze excess moisture from spinach.

Q: Can I prepare it the night before?
A: Yes. Bake, cool and refrigerate. Reheat individual portions gently in the oven or microwave.

Q: Can I freeze it?
A: Yes, although the texture can change slightly after freezing and thawing because eggs may release some moisture.

Q: How do I know it’s cooked?
A: The center should no longer look liquid or jiggle substantially when the dish is gently shaken. For a food-safety check, an egg dish should reach 160°F (71°C) internally.

Q: Can I make it vegetarian?
A: Yes—the recipe above is vegetarian.

Q: Is it keto/low-carb?
A: It is relatively low in carbohydrates because it has no pastry crust. The exact carbohydrate content depends on the milk and vegetables used.

Q: What can I serve with it?
A: A green salad, roasted vegetables, fresh fruit, avocado or whole-grain toast makes an excellent breakfast, brunch or light dinner.

Q: Can I add meat?
A: Yes. Cooked bacon, ham, chicken or turkey can be added. Make sure any meat is fully cooked before incorporating it.

Q: How long does it keep?
A: Refrigerate leftovers promptly in a covered container and use within about 3–4 days for best quality and safety.

Author
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Sara Mitchell

Sara Mitchell is an expert restaurant content creator who writes easy-to-read guides about CAVA and other Mediterranean fast-casual chains in the United States. She covers locations, menus, prices, and hours, making it simple for visitors to find nearby restaurants and what to order quickly.

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.