Preheat oven to 375°F.
Pound chicken breasts to 1/4-inch thickness.
Spread marinara sauce over each chicken breast.
Sprinkle with mozzarella cheese and roll up tightly.
Place seam-side down in a baking dish.
Top with additional marinara sauce and Parmesan cheese.
Bake for 25-30 minutes or until chicken is cooked through.