A little goes a long way with this rich dish. Offer a fresh green salad to round out the meal.
Whisk together lemon zest, lemon juice, salt, pepper, and 1/4 cup of the oil in a large bowl. Stir in parsley.
Cook pasta according to package directions for al dente, omitting salt and fat. Add asparagus during last 3 minutes of cooking. Drain and rinse well with cold water. Add pasta mixture to lemon zest mixture; toss to coat.
Cook prosciutto in a large nonstick skillet over medium-high heat, turning occasionally, until crisp, about 8 minutes; drain on paper towels. Break prosciutto into large pieces.
Top pasta mixture with prosciutto and cheese. Drizzle with remaining 2 tablespoons oil.