Chop the onion, carrots and celery and grind the prosciutto. Place the prosciutto and vegetables in a pot, add the butter (leaving 2-3 oz for later). Sauté on mid heat for a few minutes, add the ground beef, stir and add the white wine a little at a time, stirring continually
Once the wine has evaporated add the tomato paste and the same amount of water, salt and pepper to taste and cover the pot. Cook for 2 hours on a low heat, adding more water if necessary.