Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large bowl, cream together the softened butter and granulated sugar until light and fluffy.
Mix in the lemon zest and lavender buds.
Beat in the egg until well combined.
In another bowl, whisk together the all-purpose flour, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms.
Scoop tablespoon-sized amounts of dough onto the prepared baking sheet, spacing them a couple of inches apart.
Bake for 8-10 minutes until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.