PreparationFor cookies: Whisk flour, baking powder, and salt in medium bowl to blend. Using electric mixer, beat butter and both sugars in large bowl until light and fluffy. Beat in egg and maple extract. Beat in flour mixture until just blended. Divide dough in half. Flatten each half into disk; wrap disks separately in plastic and chill until firm enough to roll, about 1 hour. Preheat oven to 375°F. Line baking sheets with parchment paper. Roll out 1 dough disk on lightly floured work surface to 11-inch round, about 1/3 inch thick. Using 2-inch star-shaped cookie cutter dipped into flour, cut out cookies from dough. Place cookies on prepared baking sheets, spacing 1 inch apart. Reroll dough scraps on lightly floured surface and cut out additional cookies. Repeat with remaining dough disk. Bake cookies until lightly browned, about 12 minutes. Cool cookies on baking sheets 5 minutes, then transfer to racks and cool completely. For icing: Stir powdered sugar and milk in medium bowl until smooth (icing will be thick). Using small offset spatula or butter knife, spread icing over top of 1 cookie, then sprinkle top with sugar crystals. Repeat with remaining cookies, icing, and sugar crystals. Let cookies stand at room temperature until icing is dry and firm, at least 1 hour. (Can be made ahead. Store in single layer in airtight container at room temperature up to 5 days or freeze up to 2 weeks.) *Bright white sparkling sugar crystals are available at some supermarkets, cake and candy supply stores, and online at lacuisineus.com.
PreparationFor cookies: Whisk flour, baking powder, and salt in medium bowl to blend. Using electric mixer, beat butter and both sugars in large bowl until light and fluffy. Beat in egg and maple extract. Beat in flour mixture until just blended. Divide dough in half. Flatten each half into disk; wrap disks separately in plastic and chill until firm enough to roll, about 1 hour. Preheat oven to 375°F. Line baking sheets with parchment paper. Roll out 1 dough disk on lightly floured work surface to 11-inch round, about 1/3 inch thick. Using 2-inch star-shaped cookie cutter dipped into flour, cut out cookies from dough. Place cookies on prepared baking sheets, spacing 1 inch apart. Reroll dough scraps on lightly floured surface and cut out additional cookies. Repeat with remaining dough disk. Bake cookies until lightly browned, about 12 minutes. Cool cookies on baking sheets 5 minutes, then transfer to racks and cool completely. For icing: Stir powdered sugar and milk in medium bowl until smooth (icing will be thick). Using small offset spatula or butter knife, spread icing over top of 1 cookie, then sprinkle top with sugar crystals. Repeat with remaining cookies, icing, and sugar crystals. Let cookies stand at room temperature until icing is dry and firm, at least 1 hour. (Can be made ahead. Store in single layer in airtight container at room temperature up to 5 days or freeze up to 2 weeks.) *Bright white sparkling sugar crystals are available at some supermarkets, cake and candy supply stores, and online at lacuisineus.com.