If you are using fresh tomatoes, peel them by dipping them in boiling water for 1 minutes, then squeeze off their skin. Halve the tomatoes, scoop out their seeds without squeezing, and chop up coarsely. Put 2 tablespoons of butter and the vegetable oil in a small saucepan and turn on the heat to medium high. Cook the onion, stirring from time to time, until it becomes colored a pale gold. Add the ground veal, and turn it over several times, using a wooden spoon, to brown it all over. Add the cut-up tomato, salt, and several grindings of pepper, and with your wooden spoon turn over all ingredients two or three times. Cook at a steady but gentle simmer for 15 to 20 minutes. Cook and drain the pasta and toss it immediately and thoroughly with the sauce, swirling into it the remaining tablespoon of butter and the grated Parmesan. The sauce may be cooked a day in advance and refrigerated in a tightly sealed container or in a bowl under plastic wrap. When reheating, add a tablespoon of water, bring to a gentle simmer, stir occasionally, and cook until hot through and through. Yield: enough sauce for 1 pound of pasta, making 4 large or 6 small servings Notes: Recipe courtesy of Marcella Hazan, "Marcella Cucina" Recipe by: Cooking Live Show #CL9007 Posted to MC-Recipe Digest V1 #916 by "Angele and Jon Freeman" on Nov 19, 1997