HEAT BUTTER IN 3-QUART SAUCEPAN. SAUTE ONION, TOMATOES, ONION AND GARLIC. ADD CHICKEN BROTH AND CILANTRO, SIMMER FOR 15 MINUTES. DIVIDE CHILI PEPPERS, TORTILLAS AND AVOCADO BETWEEN BOWLS. FILL WITH SOUP LET STAND FOR A MINUTE, TOP WITH SOUR CREAM AND SERVE.