Heat oven to 375 degrees. Pour melted butter into a glass 9x13 pan. Cut biscuits into eighths. Place biscuit pieces in a large bowl, pour salsa into bowl and toss until all biscuits are evenly coated. Pour black beans in and stir until mixed in. Spoon into prepared pan and sprinkle with half the cheese. Top with bell pepper, onions and olives. Bake for 35-40 minutes or until edges are a deep golden brown. Sprinkle with remaining cheese and cook until cheese melts -- only a couple of minutes. Let stand 5-10 minutes. Serve with sour cream and salsa.