In large skillet over medium high heat, cook prosciutto until crispy, 3-5 minutes. (If skillet becomes too dry, add a bit of butter.) Remove prosciutto and set aside. Reduce heat under skillet to medium and melt butter. Add onion with pinch of salt and few turns of pepper. Cook until very soft, about 20 minutes, stirring occasionally. Add peaches and half of prosciutto; cook for about 5 additional minutes. Set aside.
Cook pasta according to the manufacturer’s directions. Drain.
In large bowl, mix cheese, yogurt and pinch of salt and pepper. Fold in hot pasta and reserved prosciutto mixture. Sprinkle additional cheese and remaining half of prosciutto over. Sauce will thicken as pasta cools slightly.