Spring is my favorite time of year, and my favorite soup is perfect for the varying temperatures of the season. Tom kha gai is a Thai soup made from coconut milk, lemongrass, fresh ginger, juice of a lime, chile paste, basil and cilantro. It is hot and sweet and lemony and limey. Just right for spring in the Northeast, when it’s cold and rainy one day and climbing up to 80 the next. The mushrooms should be fresh and not canned, whatever kind you use, and thrown in at the last minute to preserve freshness. Grocery store white button mushrooms are just fine. If you want to get fancy and make sure your chicken is nice and tender, you can pound it flat between pieces of wax paper and then submit it to a process called “velveting.” The point of velveting is to keep the meat soft and juicy. The chicken breast is coated in a mixture of egg white and cornstarch, rice wine or dry sherry and salt, marinated for up to 30 minutes, and then cooked very briefly in hot oil until the color turns to white. It’s a process from Chinese cooking that prevents chicken breast from turning into dry, mealy chunks in the cooking liquid. If you use this process to cook the chicken, add it at the end with the mushrooms. Tom Kha Gai Adapted from myrecipes.com Ingredients 1 can (14 oz.) reduced fat coconut milk 1 can (14 oz.) reduced-sodium chicken broth 6 quarter-size slices fresh ginger 1 stalk fresh lemongrass, cut in 1-in. pieces 1 pound boned, skinned chicken breast, cut into 1-inch chunks 1 cup sliced mushrooms 1 tablespoon fresh lime juice 1 tablespoon Thai or Vietnamese fish sauce (nuoc mam or nam pla) 1 teaspoon sugar 1 teaspoon Thai...