01 - Pulse granulated sugar and fresh lilac blossoms in a food processor until flowers are finely chopped and sugar becomes fragrant with pale purple hue. Set aside for later use.
02 - Whisk together all-purpose flour, baking powder, and salt in a medium bowl until thoroughly blended. Set aside.
03 - Beat unsalted butter and prepared lilac sugar in a large bowl until mixture becomes light and fluffy, approximately 2-3 minutes.
04 - Add egg and vanilla extract to the butter mixture. Beat until fully incorporated and smooth.
05 - Gradually add dry ingredient mixture to wet ingredients, mixing until just combined. Avoid overmixing to prevent tough cookies.
06 - Divide dough into two equal portions, shape into flat discs, wrap tightly in plastic wrap, and refrigerate for at least 1 hour until firm.
07 - Preheat oven to 350°F and line baking sheets with parchment paper.
08 - Roll chilled dough on lightly floured surface to 1/4 inch thickness. Cut into desired shapes using cookie cutters.
09 - Arrange cut cookies on prepared baking sheets. Bake for 8-10 minutes until edges are just beginning to turn golden brown.
10 - Let cookies rest on baking sheets for 5 minutes, then transfer to wire rack to cool completely before storing or serving.