01 - Pulse the sugar and lilac blossoms in a food processor until flowers are finely chopped and sugar is fragrant with pale purple hue. Set aside for use.
02 - Whisk together flour, baking powder, and salt in a medium bowl until evenly distributed.
03 - Beat butter and prepared lilac sugar in a large bowl until light and fluffy, approximately 2-3 minutes.
04 - Incorporate egg and vanilla extract, beating until fully combined and smooth.
05 - Gradually add dry ingredients to wet mixture, mixing until just incorporated. Do not overmix.
06 - Divide dough in half, shape into discs, wrap in plastic wrap, and refrigerate for at least 1 hour.
07 - Preheat oven to 350°F. Line baking sheets with parchment paper.
08 - Roll out dough on lightly floured surface to 1/4 inch thickness. Cut shapes using cookie cutters.
09 - Place cookies on prepared sheets and bake for 8-10 minutes, until edges are just golden.
10 - Let cookies rest on pan for 5 minutes, then transfer to wire rack to cool completely.