These impressive but simple-to-make gifts are almost too pretty to eat--yet too enticing not to. Choose a tin in the same shape for gifting these cookies, as it can be reused long after the cookies are gone.
Cookies: Line 2 large baking sheets with parchment. Beat butter with granulated sugar on medium-high speed in a large bowl until well combined, about 1 minute. Add egg, vanilla, and salt; beat on medium speed until combined. Reduce speed to low and gradually add flour, mixing just until incorporated. Divide dough into 2 equal portions. Shape into disks; wrap each in plastic and refrigerate until firm, at least 2 hours and up to 1 day.
Preheat oven to 325 degrees. Place one disk of dough on a lightly floured piece of parchment; roll out to a scant 1/4 inch thick. Transfer dough on parchment to a baking sheet and freeze until firm, about 30 minutes or up to 1 hour. Repeat with second disk.
Stamp out cookies with a 2 1/2-inch hexagonal cookie cutter; transfer to prepared baking sheets, 1 inch apart. Refrigerate until firm, 15 minutes. Gather scraps and repeat rolling, chilling, and stamping to make more shapes.
Bake cookies, rotating sheets halfway through, until set and golden on bottom, 12 to 15 minutes. Let cool completely on sheets on wire racks.
Royal icing: Beat confectioners' sugar, meringue powder, and 1/2 cup water in a large bowl on medium speed until icing is smooth and falls from beaters in a thin stream, about 4 minutes. (If icing is too thick, add more water, 1 teaspoon at a time.)
Divide icing into 3 equal portions. Tint one with Peach food coloring and another with Dusty Rose; leave third icing untinted. Transfer each to a pastry bag fitted with a 1/8-inch plain round tip (such as Ateco #6).
Trace outline of each cookie with one color of icing; fill in with same icing. Or trace outline of half a cookie with one color of icing; fill in with same icing, then trace and fill in other half of cookie with another color. Let dry completely, about 1 hour.
To coat with silver, lightly brush an iced, set cookie top with water, then turn cookie over and press onto center of a silver-leaf sheet. Flip over and trim silver flush with cookie edges with a craft knife or the tip of a paring knife. Or lightly brush half of cookie top with water, then press onto silver leaf, aligning center of cookie with sheet edge; trim. Cookies can be stored in an airtight container at room temperature up to 2 weeks.