2 1/2 cups uncooked medium shell pasta
2 lbs ground beef
2 medium onions, chopped
1 jar (14-oz) spaghetti sauce
1 can (14 1/2-oz) stewed tomatoes, undrained and finely chopped
1 jar (4 1/2-oz) sliced mushrooms, drained
1 garlic cloves, minced
1 tsp salt
1/2 tsp pepper
2 cups (16-oz) sour cream
1 package (6-oz) sliced provolone cheese
1 cup (4-oz) shredded mozzarella cheese
Cook pasta according to package directions. Meanwhile, in a large skillet, cook beef and onions over medium heat until meat is no longer pink; drain. Add the spaghetti sauce, tomatoes, mushrooms, garlic, salt and pepper. Bring to a boil. Reduce heat; simmer, uncovered, for 20 minutes, stirring occasionally. Drain pasta; place half in a greased 3-qt baking dish. Top with half the beef mixture. Layer with sour cream and provolone cheese. Top with remaining pasta and beef mixture. Sprinkle with mozzarella cheese. Cover and bake at 350 degrees for 40 minutes. Uncover; bake 5-10 minutes longer or until cheese is melted.
