Whether you dunk them in milk, pry them apart, or devour them whole, sandwich cookies are irresistible. These, with their crisp chocolate wafers and ganache filling made from fine-quality white chocolate, are so much better than that supermarket version.
by Gina Marie Miraglia Eriquez, Lillian Chou·published 2007-11-15
03Bring cream and corn syrup just to a simmer in a small heavy saucepan, then stir into melted chocolate. Stir in butter and vanilla until smooth. Cover surface with parchment paper and chill, stirring occasionally, until very thick, about 30 minutes.
04Preheat oven to 350°F with rack in middle. Butter 2 large baking sheets.
05Roll out 1 piece of dough between sheets of parchment paper into a 14- by 10-inch rectangle (1/8 inch thick). Slide dough in parchment onto a tray and freeze until dough is firm, about 10 minutes. Repeat with remaining dough.
06Cut out as many rounds as possible from first chilled square with cutter, reserving and chilling scraps, then quickly transfer cookies to a buttered baking sheet, arranging them 1/2 inch apart. (If dough becomes too soft, return to freezer until firm.)
07Sprinkle half of cookies with decorative sugar (if using), then bake cookies until baked through and slightly puffed, 10 to 12 minutes. Cool on sheet on rack 5 minutes, then transfer to rack to cool completely (cookies will crisp as they cool).
08Make more cookies with remaining dough and scraps (reroll only once).
09Beat ganache with an electric mixer at high speed just until light and fluffy. Transfer to a sealable plastic bag (snip off 1/8 to 1/4 inch from 1 corner with scissors). Pipe ganache onto flat sides of plain cookies, then top with sugared cookies to make sandwiches. Chill, layered between sheets of parchment, in an airtight container until filling is set, at least 1 hour.