Caramelized Onion and Zucchini Frittata with Fresh Herbs
Golden caramelized onions and tender zucchini give this garden-inspired frittata a naturally rich, savory flavor. Fresh basil, parsley, and chives keep it bright and summery. Naturally cheese-free, it is lovely for breakfast, brunch, or a light supper.
Serves: 6 | Prep Time: 15 minutes | Cook Time: 40 minutes | Total Time: 55 minutes
Why You’ll Love This Recipe
Slowly caramelized onion creates deep, naturally sweet flavor without cheese.
Cooking the zucchini until its moisture evaporates prevents a watery frittata.
Fresh basil, parsley, and chives keep it bright and summery.
It is prepared in one skillet and can be served warm or at room temperature.
Ingredients
2 tablespoons olive oil, divided
1 large yellow onion, thinly sliced
3 cups thinly sliced zucchini, about 2 medium zucchini
2 garlic cloves, minced
8 large eggs
¼ cup whole milk
½ teaspoon freshly ground black pepper
2 tablespoons chopped fresh basil, divided
2 tablespoons chopped fresh flat-leaf parsley, divided
1 tablespoon chopped fresh chives, divided
Instructions
1. Prepare the Oven
Preheat the oven to 375°F.
2. Caramelize the Onion
Heat 1 tablespoon of the olive oil in a 10-inch oven-safe nonstick or well-seasoned cast-iron skillet over medium-low heat.
Add the onion and cook for 12–15 minutes, stirring occasionally, until soft and golden. If it begins to brown too quickly, reduce the heat and add 1 tablespoon of water.
Transfer the onion to a plate.
3. Cook the Zucchini
Add the remaining tablespoon of olive oil to the skillet and increase the heat to medium-high.
Add the zucchini in an even layer. Cook for 6–8 minutes, stirring only occasionally, until lightly golden and its released moisture has evaporated.
Add the garlic and cook for 30 seconds, stirring constantly. Return the onion to the skillet, gently combine it with the zucchini, and spread the vegetables evenly.
4. Prepare the Egg Mixture
In a medium bowl, whisk together the eggs, milk, and black pepper.
Stir in 1 tablespoon each basil and parsley and 2 teaspoons chives.
5. Cook and Bake the Frittata
Reduce the heat to medium-low and pour the egg mixture evenly over the vegetables. Gently shake the skillet to help the eggs settle.
Cook without stirring for 3–4 minutes, or until the edges begin to set.
Transfer the skillet to the oven and bake for 12–16 minutes, or until the eggs are just set in the center. The frittata should appear slightly puffed, and a knife inserted near the center should come out without wet egg clinging to it.
For additional color, broil for 1–2 minutes, watching closely.
6. Rest and Serve
Let the frittata rest for 5–10 minutes.
Sprinkle with the remaining basil, parsley, and chives. Run a thin spatula around the edge, cut into wedges, and serve warm or at room temperature.
Cook’s Note
Choose small or medium zucchini with firm, smooth skin and slice them evenly. Larger zucchini contain more water and seeds.
Allow the zucchini’s released moisture to evaporate before adding the eggs to prevent a watery frittata.
Whole milk gives the eggs a tender texture, but 2% milk or unsweetened plain nondairy milk can be substituted.
Avoid overbaking; the eggs will continue to set while the frittata rests. The onion and zucchini can be cooked one day ahead and refrigerated.
Storage
Refrigerate leftovers in an airtight container for up to 4 days. Serve cold or at room temperature, or reheat individual wedges in a covered skillet over low heat or in a 300°F oven for about 10 minutes. Freezing is not recommended because the zucchini may release excess moisture after thawing.
Complete the Meal
Serve this frittata with our Orange, Fennel & Avocado Salad for a fresh, colorful brunch or light summer supper.