Peppermint patties inspired these chocolate shortbread cookies. You can use small snowflake, Christmas tree, or other holiday cutters to make the cutout windows. Bake the cutouts at 325 degrees until the edges are firm, 6 to 8 minutes.
Whisk together flour, cocoa, and salt. In a large bowl, beat butter with confectioners' sugar on medium-high speed until pale and fluffy. Beat in egg and vanilla. Gradually add flour mixture, beating to combine. Divide dough into 2 disks; wrap each in plastic and refrigerate until firm, about 1 hour.
Preheat oven to 325 degrees. Working with one disk at a time (keeping the other refrigerated), roll out on lightly floured parchment to a scant 1/8 inch. Cut out 60 rounds total with a 1 3/4-inch fluted round cutter. Chill and reroll scraps (if dough becomes too soft, freeze 15 minutes). Use a 1/2-inch fluted round cutter to cut out centers of half of rounds. Arrange rounds 1 inch apart on parchment-lined baking sheets. Freeze until firm, 15 minutes. Brush off excess flour with a dry pastry brush.
Bake, rotating sheets once, until edges are firm, 13 to 15 minutes. Transfer cookies on sheetsto a wire rack; let cool completely.
Place chocolate in a heatproofbowl. Heat cream in a smallsaucepan over medium-highuntil just bubbling around edges.Remove from heat; stir in peppermintextract. Pour mixtureover chocolate; let stand 10minutes, then stir until smooth.Let stand, stirring occasionally,until firm enough to spread,about 30 minutes.
Spread 1 teaspoon filling oneach uncut cookie; top withcut cookies. Sprinkle choppedcandies in window of eachtop cookie. Refrigerate until set,about 20 minutes. Assembledcookies can be stored in refrigerator up to 2 days.