Heat oven to 425*. In 13x9 inch pan, place butter. Heat in oven 2 to 3 minutes or until melted.
In a shallow dish, mix Bisquick mix and pepper. Pour milk into small bowl. Coat chicken with Bisquick mixture, then dip in milk; coat again with Bisquick mixture. Place in pan.
Bake uncovered about 30 minutes or until juice of chicken is clear when thickest part is cut.
In a small microwavable bowl, microwave barbecue sauce uncovered on High about 30 seconds or until warm. Spoon sauce evenly over chicken; top with cheese.