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 evenly distributed.
03 - Beat room temperature butter and prepared lilac sugar in a large bowl using an electric mixer until mixture appears light and fluffy, approximately 2-3 minutes.
04 - Add large egg and vanilla extract to the butter mixture. Beat until fully combined and smooth.
05 - Gradually add dry ingredient mixture to wet ingredients, mixing on low speed until just incorporated. Avoid overmixing to prevent tough cookies.
06 - Divide dough in half and shape into flat discs. Wrap tightly in plastic wrap and refrigerate for at least 1 hour to firm for easier rolling.
07 - Preheat oven to 350°F. Line baking sheets with parchment paper to prevent sticking.
08 - Roll chilled dough on lightly floured surface to 1/4 inch thickness. Cut into desired shapes using cookie cutters.
09 - Place cut cookies on prepared baking sheets. Bake for 8-10 minutes until edges are just beginning to turn golden.
10 - Let cookies rest on baking sheet for 5 minutes before transferring to wire rack to cool completely.