4 cupslow-sodium chicken broth 2(14-ounce) cans coconut milk , well-shaken 1 tablespoonsugar 1/2 poundwhite mushrooms , cleaned, stems trimmed, cut into 1/4-inch slices 1 poundboneless, skinless chicken breasts , halved lengthwise and sliced on bias into 1/8-inch-thick pieces (see illustration below) 3 tablespoonsfresh lime juice from 2 to 3 limes 2 teaspoonsred curry paste (Thai) 1Garnish 1/2 cupfresh cilantro leaves 2serrano chilies , sliced thin 2scallions , sliced thin on bias 1lime , cut into wedges 1Fresh Asian sweet basil sprigs
OPTIONAL 1Cooked long noodles or rice
1. Heat oil in large saucepan over medium heat until just shimmering. Add lemon grass, shallots, cilantro, and 1 tablespoon fish sauce; cook, stirring frequently, until just softened, 2 to 5 minutes (vegetables should not brown). Stir in chicken broth and 1 can coconut milk; bring to simmer over high heat. Cover, reduce heat to low, and simmer until flavors have blended, 10 minutes. Pour broth through fine-mesh strainer and discard solids in strainer. Rinse saucepan and return broth mixture to pan. 2. Return pan to medium-high heat. Stir remaining can coconut milk and sugar into broth mixture and bring to simmer. Reduce heat to medium, add mushrooms, and cook until just tender, 2 to 3 minutes. Add chicken and cook, stirring constantly, until no longer pink, 1 to 3 minutes. Remove soup from heat. 3. Combine lime juice, curry paste, and remaining 2 tablespoons fish sauce in small bowl; stir into soup. Ladle soup into bowls and garnish with cilantro, chilies, and scallions. Include cooked hot noodles or rice in bowl before ladling broth. Serve immediately with lime wedges.