01 - Pulse the sugar and lilac blossoms in a food processor until flowers are finely chopped and sugar becomes fragrant with a pale purple hue. Set aside for later use.
02 - Whisk together the all-purpose flour, baking powder, and salt in a medium bowl until thoroughly blended.
03 - Beat the unsalted butter and prepared lilac sugar in a large bowl until the mixture is light and fluffy, approximately 2-3 minutes.
04 - Add the egg and vanilla extract to the butter mixture. Beat until fully incorporated and smooth.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined. Avoid overmixing to prevent tough cookies.
06 - Divide dough in half and shape into discs. Wrap tightly in plastic wrap and refrigerate for at least 1 hour until firm.
07 - Preheat oven to 350°F. Line baking sheets with parchment paper and set aside.
08 - Roll out chilled dough on a 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 lightly golden.
10 - Let cookies rest on baking sheets for 5 minutes, then transfer to a wire rack to cool completely before serving.