Pound chicken breasts to an even thickness
Season both sides with salt and black pepper
Set up three bowls: flour, beaten eggs, and grated Parmesan mixed with breadcrumbs
Dredge each chicken breast in flour
Dip in beaten eggs
Coat thoroughly with the Parmesan breadcrumb mixture
Heat oil in a skillet over medium heat
Cook chicken until golden brown on both sides
Transfer chicken to a baking dish
Top with marinara sauce and mozzarella cheese if desired
Bake until the chicken is cooked through and the cheese is melted
Serve hot