When the water is boiling,core the tomatoes and slash a little X on the blossom end.Plunge fruit into boiling water 20 to 25 seconds,then remove with slotted spoon.At this point,add pasta to the boiling water.Cool and peel the tomato under cold running water.Cut into thickish wedges.Reserve... In a large saute or frying pan,heat the oil over high heat.When sizzling hot,add the zucchini and summer squash and cook,stirring and tossing until vegetables brown 4 to 6 minutes.Add the scallions,onion and garlic.Reduce heat and cook,stirring often,another 2 to 3 minutes.Add the mushrooms,reserved tomatoes,basil,salt,pepper and cayenne;bring mixture to a boil and immediately cover pan tightly and simmer 2 to 3 minutes... Remove lid and adjust seasonings to taste.Spoon sauce over drained hot pasta and add the freshly grated cheese.Makes 4 entree or 6 appetizer servings........