In a large bowl, combine the flour, baking powder, salt and pepper. Combine the cheese, mashed potatoes, eggs and milk, add to dry ingredients. In an electric skillet or deep fryer, heat 2 in. of oil to 375°. Drop batter by rounded tablespoonfuls, a few at a time, into hot oil. Fry until golden brown, about 1-1/2 minutes on each side. Serve immediately.