1. Spray a Dutch oven with vegetable oil cooking spray. Cook beef and garlic over medium-high heat, stirring frequently until meat is no longer pink. Drain and rinse. Return meat to pan; add tomatoes, sauce, paste, salt and sugar. Simmer 30 minutes.
2. Meanwhile, cook pasta according to package directions without added fat or salt. Drain. Place pasta in a 9- x 13-inch baking dish sprayed with cooking spray.
3. Preheat oven to 350° F.
4. In a small bowl, combine sour cream, cream cheese and onions. Spread evenly over pasta. Top with meat sauce.
5. Bake 25 minutes or until thoroughly heated. Sprinkle with cheese and bake 5 additional minutes or until cheese is melted. Let stand 5 minutes before serving.