Instructions

  1. Bring a large pot of lightly salted water to a boil; Add ziti pasta, and cook until al dente, about 8 minutes; drain.
  2. In a large skillet, brown onion and ground beef over medium heat; Add spaghetti sauce, and simmer 15 minutes.
  3. Preheat the oven to 350F (175C).
  4. Butter a 9x13 inch baking dish.
  5. Layer as follows: 1/2 of the ziti, Provolone cheese, sour cream, 1/2 sauce mixture, remaining ziti, mozzarella cheese and remaining sauce mixture; Top with grated Parmesan cheese.
  6. Bake for 30 minutes in the preheated oven, or until cheeses are melted.