Instructions:
Wash potatoes and cook in the boiling salted water for 30 minutes, or until tender to the insertion of a butter knife. Transfer to a colander and cool with tepid water. Peel, slice and set aside. In a large skillet, heat the olive oil, onions, and diced prosciutto. Stir to caramelize the onion, about 10 minutes. Add the garlic, diced tomatoes, and broth.
Add the sliced potatoes, stir, cover, and let simmer on very low for 30 minutes to absorb the broth. Just before serving, add the butter, chopped basil, and parsley. Salt and pepper to taste. Top with fresh-grated Parmesan (or Pecorino Romano) to your liking.