Beat the softened butter and sugar together in a mixing bowl using an electric mixer on medium speed until the mixture is light and fluffy, about 2-3 minutes, and appears pale in color.
Add the egg to the creamed mixture and beat until fully incorporated, about 30 seconds. Smell the mixture for a subtle floral aroma as the egg mixes in.
In a separate bowl, whisk together the flour, crushed lavender buds, baking powder, and salt. Gradually add this dry mixture to the wet ingredients, mixing on low speed until the dough begins to come together and no streaks of flour remain.
Scoop the dough onto a lightly floured surface and gently knead to combine. Divide the dough into two equal portions, then roll each into a 1/2-inch thick disk with a rolling pin, ensuring even thickness for uniform baking.
Cut out cookies using a cookie cutter or knife and place them onto a parchment-lined baking sheet. Space them evenly to allow for expansion during baking.
Bake in a preheated oven at 350°F (175°C) for about 10-12 minutes, or until the edges are golden brown and the centers are set. Once baked, remove from the oven and transfer to a cooling rack to cool completely, allowing the flavors to settle and the texture to firm up.
