1/3cupfinely grated Parmigiano-Reggiano cheeseplus some shavings of cheese for garnish (optional)
kosher salt and Freshly ground black pepper
2or 3 mediumzucchiniends trimmed and discarded, remainder thinly sliced into coins
4tablespoonsextra-virgin olive oildivided
1/2mediumyellow or white onionhalved lengthwise then sliced crosswise into quarter moon shapes
2garlic clovesthinly sliced
3/4cupwhole milk ricotta cheese
1handfulfresh basil leavesminced just before using, plus a few extra leaves for garnish
1handfulfresh mint leavesminced just before using, plus a few extra leaves for garnish
4to 6 ouncesthinly sliced prosciuttoor jamón, for garnish (optional)
Make The Frittata Base: In a medium bowl, whisk together the eggs and Parmigiano-Reggiano cheese, and a crank of black pepper until the yolks are just incorporated. Meanwhile, place the zucchini in a fine-mesh sieve then toss them with a large pinch of salt. Set the sieve in a bowl and set aside at least 5 minutes and up to 2 hours so they can let off some water. Use a clean towel to pat the zucchini dry and rub off some of the salt.
Make The Sautéed Onions: Heat 1 tablespoon of the oil in a 9-or-10-inch large frying pan over medium-low heat until shimmering. Add the onion, season with salt and freshly ground black pepper, and cook, stirring occasionally, until the onion is golden brown, about 12 minutes. Stir in the garlic and cook another couple of minutes until the whole mixture is golden brown. Turn the onion mixture into the eggs and stir to combine. Return the pan to the stove.
Make The Sautéed Zucchini: Heat 1 tablespoon of the oil in the large frying pan over high heat and, once the oil shimmers, add half of the zucchini. It should sit in one layer in the pan so that they get brown and don't steam. Let the zucchini cook undisturbed for a few minutes, then flip when they're golden brown.Let cook until the zucchini is just soft on the second side (they don't need to get color) and remove them to a paper towel-lined plate or baking sheet. Repeat to cook the remaining zucchini.
Cook The Frittata: Once the zucchini are all cooked add them to the egg mixture along with the ricotta and the herbs and stir until everything is evenly combined but you still have a few chunks of ricotta. Wipe out the pan and return to the stove. Add the remaining 2 tablespoons of olive oil to the pan and swirl to coat. Arrange the rack in the oven in the upper third and heat the broiler to high. Once the oil shimmers pour in the egg mixture. Cook until the outer 2 inches are beginning to set. Run a spatula around the edge to make sure the frittata is not sticking to the sides of the pan.
Place the frittata under the broiler and, keeping the door ajar and constantly keeping an eye on it, and broil until the top is just set (it should no longer be liquidy but it should jiggle a tad bit still in the center), about 3 minutes. Remove the frittata from the broiler and set aside 5 to 10 minutes before serving.
Serve The Frittata: Run a spatula around the innner edge of the pan and then slide the frittata onto a large plate or serving platter. Top the frittata with a few pieces of prosciutto, a few shavings of cheese, a handful of herbs, and a crank of black pepper and serve immediately.