Caramelized onions, sautéed red bell peppers and zucchini combined with grated Parmesan make an easy, flavorful frittata that works for breakfast, brunch, lunch or a light dinner. This simple oven-finished skillet egg dish is a great way to use seasonal vegetables and clean out the fridge.
Caramelized Onion, Pepper, Zucchini Frittata
Frittatas are extremely versatile: serve warm or at room temperature, pair with a simple green salad for lunch or add crusty bread for a satisfying dinner. They’re also a forgiving way to use up vegetables, cheeses and cooked proteins you have on hand. Below you’ll find a straightforward method for sautéing the vegetables, whisking the eggs with Parmesan, and finishing the dish in the oven for a tender, evenly set frittata.
Bell peppers and zucchini are wonderful when in season—roasting or sautéing concentrates their sweetness and texture. For this recipe, the onion is cooked slowly until lightly caramelized, then the peppers and zucchini are added and cooked briefly so they stay tender and slightly crisp. The eggs mixed with a bit of Parmesan are poured over the vegetables and baked until set.
If you don’t have an ovenproof skillet, you can cover the pan and finish cooking on low heat on the stovetop. Another method is to transfer the vegetable and egg mixture to a 9-inch deep pie plate or a square glass baking dish and bake until the eggs are fully set (the baking time will be slightly longer, about 25 minutes at 400°F).
What’s the difference between a quiche, omelet, and frittata?
Quiche is an egg custard that usually combines eggs with cream or milk, with fillings mixed into the raw custard and baked—often in a pastry crust but sometimes crustless. An omelet is typically a single-serving pan-cooked egg folded over fillings placed on top of the cooked eggs. A frittata starts by cooking the fillings (vegetables, meats) first, then mixing them with the eggs; the mixture begins on the stovetop and is finished in the oven. Omelets are normally single servings, while frittatas and quiches are usually prepared for multiple servings.
Can you freeze leftover frittata?
Yes. Cool the frittata completely, cut into individual portions and wrap each piece tightly in plastic wrap or place in freezer bags. Thaw overnight in the refrigerator, then reheat in the microwave for 30–60 seconds or warm in a low oven. Frittata portions will keep well for up to three months in the freezer.
Variations
- Swap the vegetables for whatever you have: asparagus, broccoli, mushrooms or spinach all work nicely.
- Use a food processor to speed up cutting the zucchini or peppers.
- Substitute Parmesan with goat cheese, pecorino Romano or feta, or leave out the cheese for a dairy-free version.
- Add cooked Italian sausage, diced roasted chicken or cooked chopped bacon for extra protein.
- To make a lighter frittata, use half whole eggs and half egg whites (for every whole egg replaced, use two egg whites).
- Make frittata muffins by pouring the mixture into a muffin tin and baking at 350°F for about 25 minutes—great for meal prep.
- To feed a crowd, double the recipe and bake in a 9” x 13” glass dish until set.
More Frittata Recipes You Might Enjoy
- Asparagus and Swiss Cheese Frittata
- Spinach and Feta Frittata
- Tomato and Zucchini Frittata
- Turkey and Sweet Potato Frittata
- Bell Pepper and Potato Frittata
Caramelized Onion, Red Pepper and Zucchini Frittata
Yield: 4 servings
Serving Size: 1/4th
Prep: 5 mins · Cook: 35 mins · Total: 40 mins
Cals: 186 · Protein: 13 g · Carbs: 8 g · Fat: 11.5 g · Fiber: 2 g
Ingredients
- 1 white onion, thinly sliced
- 1 medium red bell pepper, diced
- 1 1/2 cups zucchini, diced into matchsticks
- 6 large eggs
- 1/4 cup Parmesan cheese, grated
- 2 tsp olive oil
- Salt and fresh ground pepper, to taste
Instructions
- Preheat the oven to 400°F (200°C). Heat the oil in a 10-inch ovenproof skillet over medium-low heat.
- Add the sliced onion and cook, stirring occasionally, until it begins to brown and caramelize, about 10 minutes.
- Add the diced red pepper and cook 5 more minutes. Stir in the zucchini, season with salt and pepper, and cook an additional 3 minutes, stirring occasionally so the vegetables are tender but not mushy.
- In a medium bowl, whisk the eggs with the grated Parmesan, plus a pinch of salt and pepper.
- Pour the egg mixture evenly over the vegetables in the skillet, making sure the eggs cover all the vegetables. Cook on the stovetop for about 2 minutes, until the edges begin to set.
- Carefully transfer the skillet to the preheated oven and bake 10–15 minutes, until the frittata is completely set in the center. If not using an ovenproof skillet, pour the mixture into a greased 9-inch baking dish and bake for about 25 minutes.
- Remove from the oven and let rest for a few minutes. Slice into 4 wedges and serve warm or at room temperature.
Tips
For a silkier texture, let the frittata rest for 5 minutes before slicing. If you prefer a firmer brown top, place under the broiler for a minute or two—watch closely to avoid burning. Leftovers reheat well and are portable for packed lunches.
Nutrition
Per serving (1/4th): Calories 186 · Carbohydrates 8 g · Protein 13 g · Fat 11.5 g · Saturated Fat 4 g · Cholesterol 284 mg · Sodium 226.5 mg · Fiber 2 g · Sugar 4 g
