One 1/4-inch-thick slice of prosciutto (about 2 ounces), cut into 1/4-inch dice
1 large bunch of arugula, stems trimmed, leaves sliced 1/2 inch thick
Preheat the broiler and position a rack near the heat. in a bowl, gently beat the eggs with the Parmesan and a generous pinch each of salt and pepper.
Heat 1 tablespoon of the olive oil in a large ovenproof nonstick skillet. Add the prosciutto and cook over moderately high heat, stirring frequently, until barely browned, 1 to 2 minutes. Add the arugula and cook, stirring, until wilted, about 1 minute. Drizzle the remaining 1 tablespoon of oil around the outer edge of the skillet. Pour the eggs into the skillet and stir to distribute the prosciutto and arugula evenly. Cook the frittata without stirring until the edges and bottom are set but the top is still soft and runny, about 6 minutes.
Place the frittata under the broiler and cook for about 1 minute, or just until golden and set. Invert the frittata onto a cutting board, cut into 8 wedges and serve warm or at room temperature.