Heat a 10-inch crêpe pan or nonstick skillet over moderate heat. Brush the pan with some of the melted butter. Pour in a scant 1/3 cup of the crêpe batter and immediately rotate the pan to evenly coat the bottom. Cook the crêpe until lightly browned on the bottom, about 45 seconds. Flip the crêpe and cook until brown dots appear on the other side, about 15 seconds longer. Transfer the crêpe to a large baking plate covered with parchment paper. Continue making crêpes with the remaining batter, brushing the pan with the remaining melted butter as needed.