JAM-FILLED PLAYING CARD COOKIES

Steps:

• Sift confectioners sugar into a large bowl, then beat with butter and zest with an electric mixer at medium speed until pale and fluffy. Beat in yolk, then beat in flour and salt.
• Quarter dough and roll out each quarter between sheets of parchment or wax paper into an approximately 9- by 7-inch rectangle (3/4 inch thick). Stack rectangles, still between paper, on a baking sheet and freeze at least 30 minutes.
• Preheat oven to 350°F.
• Transfer 1 paper-enclosed rectangle to a work surface (keep remaining rectangles frozen). Remove top sheet of paper and replace it loosely. Flip over paper-enclosed rectangle and discard paper now on top.
• Trim dough to a 71/2- by 6-inch rectangle with a sharp knife and a ruler. Cut lengthwise into thirds, then crosswise into thirds to form 9 (2 1/2- by 2-inch) rectangles.
• Carefully transfer cookies with a metal spatula to a buttered baking sheet and bake in middle of oven until edges are just pale golden, about 10 minutes. Cool on baking sheet on a rack 5 minutes, then transfer to racks to cool completely.
• Cut and bake 9 more cookies in same manner.
• Then make "card" cookies from remaining 2 dough rectangles: Roll out and cut in same manner as above, but before baking, use cookie cutters to cut out shapes from 2 corners of each card.
• Do not cut too close to edge or cookie will break. Bake cookies in same manner as solid ones.
• Arrange 9 solid cookies, bottom sides up, on a work surface and spread each with 1 1/2 teaspoons warm strawberry jam. Top each with a cutout cookie, pressing gently to help adhere. If necessary, spoon some of remaining jam into cutouts. Sandwich remaining cookies with warm apricot jam.