Cream butter; gradually add sugar, beating well at medium speed of an electric mixer. Add egg and vanilla; beat well. Combine 2-1/4 cups flour, soda, and salt; add to creamed mixture alternately with buttermilk, mixing well. Add remaining 1/4 cup flour if dough seems very sticky. Cover and chill 8 hours. Work with one-fourth of dough at a time, and store remainder in refrigerator. Place stockinette cover on rolling pin; flour well. Roll dough to 1/16-inch thickness on a lightly floured pastry cloth. Cut with a 3-inch round cutter, and carefully place on lightly greased cookie sheets. Bake at 375 degrees for 6 to 8 minutes or just until cookies begin to brown around edges. Cool slightly on cookie sheets, and sprinkle with superfine sugar. Remove cookies to wire racks, and cool completely. Repeat procedure with remaining dough. Store in airtight OLD FASHIONED TEACAKES: Roll dough to 1/4-inch thickness. Cut as directed above. Bake at 375 degrees for 8 to 10 minutes. Makes about 2 dozen. ----