The recipe yield is:
combine sour cream, cumin, chili powder and salt; set aside. With fork mash 1/2 cup black beans; combine with remaining black beans and 2 Tbs sour cream mixture. With fork mash avocados with lemon juice. In 4 cup glass bowl layer 1/2 bean mixture, all of avocado mixture, 1/2 remaining sour cream mixture, lettuce, remaining bean mixture, cheese, tomatoes and remaining sour cream mixture. Top with olives. Serve at room temperature with chips.