In a way, the frittata is the lazy cook’s omelette, owing to the fact that, well, you never really have to get around to that not-so-easy folding part. Just let the chips (or eggs, in this case) fall where they may.
Preheat the oven to broil.
In a medium-sized bowl, using a fork, beat together the eggs, Parmesan, salt, and pepper. Heat the butter in a 12-inch nonstick, oven-safe sauté pan over medium-high heat.
Once melted, add the onion and ham to the pan and sauté for 2-3 minutes. Pour the egg mixture into the pan and stir with a rubber spatula. Cook for 4-5 minutes or until the egg mixture has set on the bottom and begins to set up on top. Sprinkle the parsley on top.
Place the pan into the oven and broil until lightly browned and fluffy, about 3-4 minutes. Remove from the pan and cut into 6 servings. Serve immediately.