Sweet potato and leek soup

Leek soup is traditionally made with white potatoes, but this recipe is a delicious twist on the old favorite. Made with sweet potatoes, it is the ideal dish for a fall day—or a few fall days, since it makes enough for 6 servings. Here's a trick to the preparation: Leeks often contain sand in between their layers, so before you make this soup, trim away most of the dark green tops and the roots, leaving the root end intact to hold the layers together. Then, slice the leek lengthwise to within a half inch of the root end. Hold the leek by the root end, fan open the layers, and rinse thoroughly under cold running water. After that, you'll be all good to go!