When the going gets rough, make soup. The icy winds are blowing, and there's only one antidote to the cold. Soup has the power to soothe your soul and warm you from the inside out. After a hard day, sit down to a bowl of Creamy Sweet Potato and Pecan Soup, and you'll understand what comfort food is all about.

Sweet potatoes and pecans are a Southern flavor combination usually reserved for desserts, but the pair works magic in this soup with a savory twist. The natural sweetness of the sweet potatoes gets a subtle nuttiness from pecans, cooked and puréed along with the onions and sweet potatoes.

This time of year you can find a rainbow assortment of sweet potatoes at well-stocked groceries and food co-ops. If you want a deep orange soup, go for the Garnet yams. They are the darkest red-orange, a sign of high antioxidant content. The most common varieties are Beauregard and Jewell yams, which are a lovely orange color inside.

There are also yellow-fleshed varieties, including Japanese purple-skinned Satsumaimo. If you're leaning toward a subtler color, look for white sweet potatoes, like the O'Henry variety I've been buying at my co-op. The most dramatic sweet potato is the Stokes Purple, which is a deep purple hue all the way through.

The big plus of cooking a sweet potato and puréeing it for soup is that the finished dish will be creamy without needing any kind of binder or thickener, no flour-based roux, simply the natural body of the vegetable itself. The nuts thicken a little and add richness, too.

An essential element for this soup is the pecan and sage garnish. The soup is kept simple, and the sprinkling of sizzled sage adds a musky herbal flavor and scent that sets off the sweetness of the sweet potatoes. Toasted pecans add crunch and call out those in the soup.

Stay warm and well-fed with creamy sweet potato soup.

Robin Asbell is a cooking instructor and author of "Big Vegan" and "Plant-Based Meats." Find her at robinasbell.com.