Bring a large pot of lightly salted water to a boil. Add Sweet Potato Ribbons and cook for 4-5 minutes until softened; drain and set aside. In a large skillet, melt butter over medium heat. Stir in cream and season with pepper. Cook 6-8 minutes, stirring constantly. Add Parmesan cheese, stirring thoroughly until mixed. Blend in the pesto, and cook for 3 to 5 minutes, until thickened. Stir in Sweet Potato Ribbons, cook for another 2-3 minutes. Turn off heat and add halved tomatoes.