Pour tomatoes into blender or food processor. Add basil, tarragon, salt and pepper; puree until smooth. Melt margarine in large frying pan; saute garlic over medium heat for 1 minute. Add chicken breasts, fry, turning once or twice, until golden on both sides. Turn chicken fleshy side down and cover with tomato mixture. Bring to a boil; reduce heat and simmer 15 minutes until tender. Remove chicken and place fleshy side up, in a warm oven-proof dish. Stir parsley into sauce and spoon over chicken breasts. Sprinkle with cheese; place under broiler 1 minute, until cheese melts. Makes 4 servings.