01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together flour, baking powder, and salt in a medium bowl.
03 - Combine lavender and lemon zest in a small bowl. Rub together with fingers to release oils and fragrance.
04 - Beat butter and sugar in a large bowl until light and fluffy, about 2-3 minutes.
05 - Beat in egg, then add vanilla extract and lemon juice. Mix until combined.
06 - Stir in the lavender-lemon zest mixture.
07 - Gradually add dry ingredients to wet mixture, mixing just until combined. Do not overmix.
08 - Scoop tablespoon-sized portions onto prepared baking sheets, spacing 2 inches apart.
09 - Bake for 10-12 minutes until edges just begin to turn golden.
10 - Let cookies cool on baking sheets for 5 minutes, then transfer to wire rack. Dust with powdered sugar once completely cool.