If you stack the finished cookies in a tin or other airtight container, place waxed paper between the layers to protect the chocolate decoration.
- 1/4 recipe Basic Sugar-Cookie Dough
- 1 tablespoon finely grated orange zest
- 2 ounces bittersweet chocolate, finely chopped
Preheat oven to 350 degrees, with racks on upper and lower thirds. On a piece of parchment paper, pat out dough to 1/2 inch thick. Sprinkle zest evenly over top; knead to incorporate.Transfer to a cookie press; pipe shapes, about 1 inch apart, onto ungreased baking sheets.
Bake cookies in upper and lower thirds of oven, switching positions of sheets halfway through, until edges are light golden, about 15 minutes. Transfer to wire racks to cool completely.
Set a small heatproof bowl over a pan of simmering water; add half the chocolate to bowl, and stir until melted and smooth. Add the remaining chocolate; remove bowl from heat. Stir until smooth. Transfer chocolate to a pastry bag fitted with a very small (less than 1/16 inch) plain round tip, such as Wilton #1.
Transfer cookies to a sheet of parchment paper. Pipe chocolate in a zigzag pattern over tops. Let stand until chocolate has set. Store in airtight containers at room temperature, up to 5 days.