1 lb. kielbasa sausage, casing removed
1 medium onion, chopped
2 (14.5 oz.) cans Hunt's diced tomatoes with basil, garlic and oregano
1 (6 oz.) can Hunt's tomato paste
3 c. (6 oz.) twists pasta, cooked according to directions and kept warm
2 c. (8 oz.) shredded Mozzarella, divided

Cook sausage and onion over medium-high heat in skillet until crumbled and no longer pink. Drain. Blend in tomatoes and paste. Simmer for 5 minutes. Remove from pan and keep warm. Place half of cooked pasta in skillet. Pour half of the tomato-meat mixture over pasta. Sprinkle with 1 cup Mozzarella cheese. Repeat layers. Cover and cook over medium heat until heated through and cheese melts. Remove from heat and let stand for 1 minute.