01 - Preheat oven to 350°F, positioning rack in the center.
02 - Heat 1 tablespoon olive oil in a 9-inch oven-safe nonstick skillet over medium heat. Add pancetta and cook for 3-4 minutes, stirring occasionally, until crisp. Remove pancetta with a slotted spoon and set aside, leaving rendered fat in pan.
03 - Add remaining 1 tablespoon olive oil, zucchini, and onion to skillet. Sauté for 5-6 minutes until vegetables are soft and lightly golden.
04 - In a large bowl, whisk together eggs, milk, Parmesan, parsley, basil, thyme, salt, and pepper until well combined.
05 - Stir cooked pancetta into zucchini-onion mixture. Pour egg mixture evenly over vegetables and pancetta in skillet.
06 - Cook on stovetop for 2-3 minutes until edges begin to set.
07 - Transfer skillet to oven. Bake for 10-12 minutes until frittata is puffed and just set in center.
08 - Let cool for a few minutes, then slice into wedges and serve warm or at room temperature.