Heat a covered 4- to 5-quart saucepan of salted water to boiling over high heat. Add pasta and cook as label directs, stirring occasionally.

Place spinach in colander. Drain pasta over spinach in colander to wilt spinach. Return pasta mixture to same saucepan.

Meanwhile, in 10-inch skillet, melt butter over medium-high heat. Add prosciutto and shallots and cook for 2 minutes, stirring frequently.

Reduce heat to low. Add cheese, milk and pepper and stir until sauce is smooth.

Pour sauce over pasta mixture; toss until well combined.