01 - Pulse granulated sugar and fresh lilac blossoms in a food processor until flowers are finely chopped and sugar becomes fragrant with a pale purple tint. Set aside for later use.
02 - Whisk together all-purpose flour, baking powder, and salt in a medium bowl until evenly distributed.
03 - Beat room temperature unsalted butter and prepared lilac sugar in a large bowl until mixture is light and fluffy, approximately 2-3 minutes.
04 - Add egg and vanilla extract to the butter mixture, beating until fully incorporated and smooth.
05 - Gradually add dry ingredients to the wet mixture, mixing on low speed just until flour disappears. Do not overmix.
06 - Divide dough in half and shape into flat discs. Wrap tightly in plastic wrap and refrigerate for at least 1 hour or until firm enough to roll.
07 - Preheat oven to 350°F. Line baking sheets with parchment paper and set aside.
08 - On a lightly floured surface, roll out chilled dough to 1/4 inch thickness. Cut into desired shapes using cookie cutters.
09 - Arrange cut cookies on prepared baking sheets, leaving 1 inch between each. Bake for 8-10 minutes or until edges are just beginning to turn golden.
10 - Let cookies rest on baking sheet for 5 minutes, then transfer to a wire rack to cool completely before serving or storing.