Cheesy Shell Lasagna

In a nonstick skillet, cook the beef, onions and garlic over medium heat until meat is no longer pink; drain. Stir in the tomatoes, spaghetti sauce and mushrooms. Bring to a boil. Reduce heat; simmer, uncovered, for 20 minutes. Meanwhile, cook pasta according to package directions; drain.

Place half of the pasta in an ungreased 13-in. x 9-in. x 2-in. baking dish. Top with half of the meat sauce, sour cream and provolone cheese. Repeat layers. Sprinkle with mozzarella cheese.

Cover and bake at 350 degrees F for 35-40 minutes. Uncover; bake 10 minutes longer or until the cheese begins to brown. Let stand for 10 minutes before cutting.

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