Sweet potatoes are the starch that fuels me through winter's cold and dreary evenings. Abundant and versatile, our local sweet potatoes are far more flavorful and distinctive than those shipped from down south. Thanks to our shorter growing season, the varieties cultivated here are smaller, with more intense flavors.

Let's clear up any confusion: Sweet potatoes are not yams and they are not potatoes. Yams are starchy, bland-tasting roots, native to Africa and Asia. Sweet potatoes are members of the Morning Glory plant family and they hail from South and Central America with the first traces dating as far back as 8,000 BC. Potatoes belong to the nightshade family that includes peppers, eggplant and tomatoes. Sweet potato varieties are orange, pale gold, and purple. They can be fat and bulbous or thin and gnarled.

Find local sweet potatoes in our winter farmers markets and local food co-ops. Choose those that are firm to the touch, without scars or bruises, and that are heavy for their size. Store sweet potatoes in a cool, dry, dark place. Do not refrigerate or keep in plastic because it will trap moisture and speed up a decline.

As a general guide, the sweet potato varieties with darker orange flesh are super sweet, moist and best mashed, cut into wedges, or simply baked and topped with butter. Those with pale gold or copper skins are mildly sweet and very creamy, perfect for adding bulk to soups and stews. Deep red and purple Asian varieties are earthier, drier and less sweet, and work nicely in stir-fries or cubed and roasted.

Roasted sweet potatoes wedges and cubes are satisfying and quick to make. Toss these with a little oil and sprinkle with coarse salt, then spread out on a baking sheet and place in a hot (400-degree) oven until nicely caramelized around the edges, shaking the pan occasionally so they don't stick, about 15 to 25 minutes. Serve these on dark green salads or on pizza; tangle in pasta; fold into curry; or top with a poached or fried egg.

The best way to prepare sweet potatoes for purées or soup is to roast them whole. This concentrates their earthy-sweet nature and is easier than boiling or steaming. Use this basic recipe for sweet potato, purée and then play with the variations. Seasoned to be tangy, hot, spiced or herbed, sweet potato purée makes a fine side to roast chicken, pork, or lamb and the base for a sumptuous soup.

Beth Dooley is the author of "In Winter's Kitchen."