BLEND 1 can of beans and half the broth in blender until smooth. Cook and stir onions, garlic and cumin in hot oil in large saucepan on medium heat 3 min. Add bean puree; mix well.
ADD second can of beans and broth to blender; blend until smooth. Add to bean mixture in saucepan with remaining can of beans and salsa; mix well. Bring to boil on medium-high heat; simmer on low heat 15 min., stirring occasionally.
SERVE topped with sour cream.