Pound the chicken breasts until they are about 3/4 inches thick. Season with salt and pepper. Dredge into flour until they are lightly coated.
Heat olive oil and sunflower oil in a large frying pan. Cook for about 4 minutes per side, or until they are browned on each side.
Pour the tomato sauce into the pan. Add garlic. Simmer about 15 minutes more. Serve hot with cooked pasta, mashed potato, rice or polenta. Garnish with chopped parsley (optional).