Instructions:
Step 1: Preheat your oven to 375°F (190°C).
Step 2: In a large oven-safe skillet, heat olive oil over medium heat. Add diced onion and sauté until translucent, about 3-4 minutes.
Step 3: Add the zucchini slices and cook for another 5 minutes, stirring occasionally, until they begin to soften.
Step 4: Stir in the cherry tomatoes and cook for 2 more minutes.
Step 5: In a large bowl, whisk together the eggs, mozzarella, Parmesan, parsley, salt, and pepper.
Step 6: Pour the egg mixture evenly over the vegetables in the skillet. Cook without stirring for about 5 minutes, until the edges begin to set.
Step 7: Transfer the skillet to the preheated oven and bake for 10-12 minutes, or until the frittata is fully set and lightly golden on top.
Step 8: Let the frittata cool for a few minutes before slicing and serving.
Storage Information:
Store leftover frittata in an airtight container in the refrigerator for up to 3 days. Reheat slices in the microwave or a low oven until warmed through. You can also freeze individual slices for up to 1 month; thaw overnight in the fridge before reheating.