Related to neither the potato nor the yam, with which it's often confused, the sweet potato is a starchy root vegetable native to the Americas. The orange-fleshed variety popular in the United States is relatively rare in other parts of the world; in Asia, where the great majority of sweet potatoes are now grown, you are more likely to find slightly less sweet, white-fleshed types. The tubers can vary widely in texture, color, and sugar content, from creamy to fluffy, deep orange to nearly white, with flavor profiles that bring to mind pumpkin, vanilla, and sometimes toasted nuts. Their natural sweetness makes them an obvious choice for desserts, such as sweet potato pie, but they're equally good in savory preparations, whether simply roasted with a bit of salt, puréed into soup, or baked into a gratin.
HOW TO BUY
Choose small to medium sweet potatoes that feel heavy for their size, and buy them shortly before you plan to use them. Avoid sprouted tubers and those that have been stored in refrigeration.
HOW TO STORE
Store whole sweet potatoes in a cool, dark place for up to a week. Don't refrigerate them; cold temperatures will negatively affect their flavor and cause them to toughen.
HOW TO PREPARE
Scrub them well under running water; you can peel them or leave the skin on, depending on your preference and cooking method. Keeping raw, cut pieces in water will help prevent discoloration.