COOK and stir onion, garlic and cumin in oil over medium heat in large saucepan 3 min.

PLACE 1 can of the undrained beans and half of the broth in blender or food processor container; cover. Blend until pureed. Add to ingredients in saucepan. Repeat with second can of undrained beans and remaining broth. Add remaining can of beans and salsa to saucepan mixture; mix well.

BRING to a boil on medium-high heat. Reduce heat to low; simmer 15 min., stirring occasionally. Ladle soup into serving bowls. Drizzle each serving with 1 Tbsp. sour cream.