INSTRUCTIONS:

1. Preheat your oven to 350°F (175°C).
2. Heat one tablespoon of olive oil in a large oven-safe skillet over medium heat. Add the diced onion and cook until translucent, about 3-4 minutes.
3. Add the sliced zucchinis to the skillet and cook until they are tender, about 5-6 minutes. Season with salt and pepper to taste.
4. In a separate bowl, whisk together the eggs, milk, and grated Parmesan cheese until well combined.
5. Pour the egg mixture over the cooked zucchini and onions in the skillet. Gently stir to distribute the vegetables evenly.
6. Cook the frittata on the stovetop for 3-4 minutes, allowing the edges to set.
7. Transfer the skillet to the preheated oven and bake for 12-15 minutes, or until the frittata is set in the center and slightly golden on top.
8. Once cooked, remove the frittata from the oven and let it cool for a few minutes.
9. To serve, slide the frittata out of the skillet onto a cutting board. Cut into wedges and garnish with chopped fresh herbs if desired.
10. Enjoy your delicious zucchini frittata warm or at room temperature, either on its own or with a side of mixed greens or crusty bread.