Place chicken on wax paper and flatten to 1/4" thick, using meat mallet. Combine eggs, salt, and pepper. Dip breasts into egg mixture, then roll each in bread crumbs. Brown in hot oil in a large skillet; drain on paper towels. Place chicken in lightly greased 13"x9"x2" pan. Drain oil from skillet. Combine tomato sauce, basil, garlic in skillet. Bring to a boil and simmer 10 minutes, or until thickened. Stir in butter. Pour mixture over chicken and sprinkle with Parmesan cheese. Cover and bake at 350 for 30 minutes. Uncover and arrange Mozzarella slices on top. Bake an additional 10 minutes.