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 use.
02 - Whisk together all-purpose flour, baking powder, and salt in a medium bowl until uniformly blended.
03 - Beat unsalted butter and prepared lilac sugar in a large bowl until mixture appears light and fluffy, approximately 2-3 minutes.
04 - Add large egg and vanilla extract to butter mixture, beating until fully combined and smooth.
05 - Gradually add dry ingredient mixture to wet ingredients, mixing until just incorporated. Avoid overmixing to prevent tough cookies.
06 - Divide dough in half, shape into flat discs, wrap tightly in plastic wrap, and refrigerate for minimum 1 hour to firm.
07 - Preheat oven to 350°F. Line baking sheets with parchment paper for easy cleanup and to prevent sticking.
08 - Roll chilled dough on lightly floured surface to 1/4 inch thickness. Cut into desired shapes using cookie cutters, transferring to prepared baking sheets.
09 - Place baking sheets in preheated oven and bake for 8-10 minutes until edges appear just barely golden. Centers should remain soft.
10 - Allow cookies to rest on baking pan for 5 minutes, then transfer to wire rack to cool completely before serving or storing.