Melt chocolate over a double boiler (or in a microwave oven). Meanwhile, place bananas, in chunks, and yogurt into a blender, and pulse to just mix. Add remaining ingredients and blend briefly. When chocolate is melted, add to the banana mixture and blend to just mix. (It’s okay if the chocolate is still quite hot.) Pour pudding into individual serving dishes, cover tightly with plastic wrap, and chill for at least 2 hours. Serve with fresh berries on top.