Brown the sausage in a large skillet. Once browned add in jar of marinara sauce and warm through.
Cook penne according to package instructions and drain.
Mix pasta and sauce together.
Place in a large baking dish. Top with mozzarella and Parmesan.
Bake at 350 for about 30 minutes. Place under the broiler for 2-3 minutes to get a nice bubbly crust