Baked Ziti

1 lb dry ziti pasta
1 onion
1 lb hamburger
2 (26 oz jars) spagetti sauce
6 oz sliced provolone cheese
1 1/2 c. sour cream
6 oz shredded mozzarella cheese
2 T. parmesan cheese

Cook ziti for 8 min until dente.
Brown beef and onion.
Add spaggetti sauce, simmer.
Layer in 9x13 pana:
1/2 ziti, provolone cheese, sour cream. 1/2 sauce mixture, then remaining. Top with grated parmesan cheese.
Cover and bake for 30 minutes at 350.

*serves 10