1. Preheat oven to 180 degrees celsius. 2. Using a rolling pin, pound the chicken breasts between sheets of cling film until thin. 3. Mix the breadcrumbs with the parmesan in a bowl. Dip the chicken into the egg, then coat with the breadcrumb mixture. 4. In a medium-sized pan on a high heat, fry the chicken for 5 minutes on each side. 5. Pour the heated tomato sauce into a shallow ovenproof dish and place the chicken on top. 6. Top with mozzarella and the remaining parmesan. Bake in the oven for 15-18 minutes or until cheese is melted and golden on top.