• 5 eggs
• 1/4 teaspoon salt
• Freshly ground pepper
• 1 tablespoon olive oil
• 1 leek (white part and 1 inch green), washed well and coarsely chopped, about 1 cup
• 2 ounces prosciutto (2 thin, but not paper-thin, slices), sliced crosswise into 1/4-inch strips
• 3/4 to 1 pound roasted boiling potatoes, cut into 1/4-inch dice (1 1/2 cups)
• 1 teaspoon minced fresh rosemary
• 1/3 cup grated Asiago cheese
• 1 small tomato, diced, for garnish, optional
• Chopped Italian parsley, for garnish, optional

Step 1Lightly beat eggs with salt and pepper to taste.

Step 2Heat oil in 10-inch nonstick, ovenproof skillet over medium heat. Add leek and saute until just starting to soften, about 2 minutes. Add prosciutto and saute until leek is soft, 1 to 2 minutes. Remove half of leek mixture and set aside.

Step 3Add potatoes and rosemary to skillet and toss to heat potatoes, 1 minute. Reduce heat to medium-low and add eggs. Do not stir. Cook just until bottom of eggs is set, 3 to 4 minutes. Top should still be wet.

Step 4Sprinkle with cheese and reserved leek mixture. Broil 4 inches from heat source until frittata is golden and sizzling, about 2 minutes.

Step 5Invert frittata onto cutting board, sprinkle with tomato and parsley, and cut into wedges.