In a non-stick skillet , cook the beef, onions and garlic over medium heat until meat is no longer pink; drain.
Stir in the tomatoes and spaghetti sauce, bring to a boil, reduce heat and simmer, uncovered, for 20 minutes
Meanwhile cook pasta according to package directions, drain.
Pace half of pasta in an ungreased 13-in x 9-in baking dish. Top with half the meat sauce, sour cream, and provolone cheese. repeat the layers. sprinkle with mozzarella cheese.
Cover and bake at 350ºF for 35-40 minutes. Uncover and bake 10 minutes longer, or until the cheese begins to brown.