Citrus-Scented Black Bean Soup with Chipotle Cream

Heat oil in a large saucepan over medium heat. Add onion, cover and cook, stirring occasionally, until browned, 4 to 5 minutes. Add cumin and cook, stirring, until fragrant, about 30 seconds. Add beans, water, orange zest and juice, salt and pepper; increase heat to medium-high and bring to a boil, stirring often. Transfer to a blender with cilantro, lime juice and 3 tablespoons sour cream. Puree until smooth. (Use caution when pureeing hot liquids; see Tip.) Combine the remaining 1 tablespoon sour cream and ground chipotle in a small bowl. Serve the soup garnished with the chipotle cream and scallions.