Combine butter with mango chutney, lime juice and cayenne pepper blending well. Shape into a roll, wrap in foil or wax paper and chill for about 2 hours in freezer. Preheat broiler. Brush chicken pieces lightly with oil; season with salt and pepper. Broil at least 30 minutes, turning at least twice and brushing again with oil. Divide mango butter into 8 equal rounds and lay one on each portion of hot broiled chicken. Makes 4 servings.