Preheat oven to 425 degrees. Mix Bisquick, baking powder, and buttermilk until blended. On a floured board need dough about ten times, dough should be easy to roll out, but not dry. Roll dough out to 1/2" thickness and cut biscuits 2 1/2" diameter. Place biscuits on an ungreased baking dish, or cookie sheet and brush the tops of the biscuits with melted butter if you desire. Bake biscuits 8 - 12 minutes or until done.