Place boneless chicken breasts between two pieces of plastic wrap. Starting in the center and working out to the edges, pound lightly with the flat side of a meat mallet until the chicken is even in thickness.
In a medium bowl, combine breadcrumbs, parmesan cheese and dry Italian dressing mix; mix well. In a shallow bowl or pie plate, whisk together milk and eggs until well blended. In a separate shallow bowl or pie plate, place 1 cup of flour. Coat each chicken breast with flour, shaking off excess. Dip into milk mixture, then into breadcrumb mixture, coating evenly and pressing into chicken.
Heat about 1/4-inch of oil inn a large heavy skillet over medium heat. Add chicken and cook for 5 to 6 minutes on each side or until golden brown.
In a large casserole dish or lasagna pan, pour 2 jars of spaghetti sauce in and place fried chicken on top of sauce in one layer. Top each piece of chicken with a thick slice of cheese and bake at 350 degrees for 30 minutes or until sauce is hot and bubbly and cheese is melted. Serve with hot spaghetti noodles and garlic bread.