PLACE CANNED BEANS IN BLENDER A SMALL AMOUNT AT A TIME TILL BLENDED COMPLETELY. IN SAUCEPAN MELT BUTTER, ADD ONION, GARLIC, CILANTRO, CUMIN, CHILI POWDER, CELERY AND SALT. COOK TILL ONION IS TRANSPARENT. ADD TOMATO SAUCE, BLENDED BLACK BEANS, AND CHICKEN BROTH. SERVE HOT AND TOPPED WITH SOUR CREAM.