01 - Pulse the granulated sugar and fresh lilac blossoms in a food processor until flowers are finely chopped and sugar becomes fragrant with a pale purple hue. Set aside for use.
02 - Whisk together the all-purpose flour, baking powder, and salt in a medium bowl until evenly distributed.
03 - Beat the room temperature butter and prepared lilac sugar in a large bowl until the mixture appears light and fluffy in texture.
04 - Incorporate the large egg and vanilla extract into the butter mixture, beating until fully combined and smooth.
05 - Gradually add the dry ingredient mixture to the wet ingredients, mixing gently until just incorporated and no dry streaks remain.
06 - Divide the dough into two equal portions, shape each into a disc, wrap tightly in plastic wrap, and refrigerate for at least 1 hour.
07 - Preheat the oven to 350°F and line baking sheets with parchment paper for easy cleanup.
08 - Roll out the chilled dough on a lightly floured surface to 1/4 inch thickness, then cut into desired shapes using cookie cutters.
09 - Arrange cookies on the prepared baking sheets and bake for 8 to 10 minutes until the edges just begin to turn golden brown.
10 - Let the cookies rest on the baking pan for 5 minutes before transferring to a wire rack to cool completely.