01 - Preheat oven to 350°F. Line baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, and salt until evenly blended.
03 - Using a mortar and pestle or spice grinder, lightly crush the dried lavender with lemon zest to release essential oils; set aside.
04 - In a large bowl, beat softened butter and granulated sugar until light and fluffy, approximately 2 minutes.
05 - Beat in the egg, vanilla extract, and fresh lemon juice until mixture is smooth and fully incorporated.
06 - Mix in the prepared lavender-lemon zest mixture until evenly distributed throughout the batter.
07 - Gradually add dry ingredients to wet ingredients, mixing gently until just incorporated and no flour streaks remain.
08 - Scoop tablespoon-sized balls of dough onto prepared baking sheets, leaving 2 inches of space between each cookie.
09 - Bake for 10 to 12 minutes, or until edges are lightly golden and centers are set.
10 - Let cookies rest on baking sheet for 2 minutes, then transfer to wire rack to cool completely before serving.