Sweet potatoes make an excellent addition to tomato sauce—they are sweet and creamy and balance acidic tomatoes perfectly. Slideshow: Great Spaghetti Recipes
In a large saucepan, cover the potato with enough water to cover by 2 inches. Boil until tender, about 20 minutes. Drain and transfer the potato to a blender. Add the tomato, water, cream and olive oil and puree until smooth. Season with salt and pepper and serve hot.
The sauce can be refrigerated for 1 week or frozen for 1 month.