Heat oil in a deep 12-inch saute pan over medium-high heat. Cook onion and green pepper for 6 to 7 minutes until softened and browned at the edges.
Add beef and brown for 6 to 7 minutes, breaking it into crumbles and cooking to 160°F. Drain excess fat and stir in garlic for 30 seconds.
Add penne, broth, Worcestershire, salt and pepper. Simmer uncovered over medium-low heat for 11 to 14 minutes, stirring often and adding reserved water only if needed before the pasta becomes tender.
Stir in milk and warm gently for 1 minute. Remove from heat and wait 1 minute for bubbling to stop.
Fold provolone into the warm pasta a small handful at a time until melted. Serve promptly so the coating remains soft.