Preheat oven to 350 degrees F (175 degrees C). In a shallow dish, combine the flour, bread crumbs, Parmesan cheese, and egg. Season the chicken breasts with salt and pepper. Dip the chicken breasts in the egg mixture, then in the breadcrumb mixture. Heat the olive oil in a large skillet over medium heat. Cook the chicken breasts for 2-3 minutes per side, or until golden brown and cooked through. Transfer the chicken breasts to a baking dish. Top the chicken breasts with the marinara sauce and mozzarella cheese. Bake in the preheated oven for 10-15 minutes, or until the cheese is melted and bubbly. Serve immediately.