Preheat the oven to 400ºF / 200ºC degrees and grease a 9 x 13-inch (23 x 33 cm) baking dish.
Cook the ziti according to the package instructions, then drain.
Heat a little oil in a large skillet, add the onion, and cook until softened.
Add the ground beef and cook until browned.
Stir in the marinara sauce and simmer for 5 minutes.
Add half of the cooked ziti to the baking dish and top with half of the meat mixture.
Layer the provolone cheese on top, followed by the sour cream, then repeat with the remaining ziti and meat sauce.
Top with shredded mozzarella and parmesan cheese.
Bake for 30–40 minutes, until the cheese is melted and the sauce is bubbling.
Serve hot with crusty white bread.