Bring 4 to 6 quarts of water to a rolling boil, add salt to taste and the Elbows; stir gently. Cook pasta according to package directions; remove from heat and drain well. Meanwhile, in a small pot bring the broth to a boil and add the sweet potato; cook 3 to 4 minutes or until soft, then remove from heat. In a blender combine the sweet potato, broth, Tomato & Basil Sauce and salt; cover and blend until smooth. In a very large skillet bring the blended sauce mixture to a low simmer. Remove from heat; slowly stir in cheese until melted (mixture may appear curdled). Stir pasta into the sauce in skillet. Let stand 5 minutes. Stir in enough milk to make a creamy consistency. Serve topped with fresh basil.