Combine first 5 ingredients; make a well in center. Stir together buttermilk, butter, and egg. Add to flour mixture, stirring just until moistened.
Heat cast-iron cornstick pans in a 450° oven 5 minutes or until hot. Remove pans from oven, and brush lightly with oil. Spoon batter evenly into hot pans.
Bake at 450° for 18 minutes or until golden brown. Remove from pans immediately; cool slightly on wire racks.