Using a mortar and pestle, grind up the lavender until it is very fine, nearly a powder.

Using a stand mixer with a paddle attachment, mix the butter, sugar, and lavender until combined.

Add vanilla and mix just enough so the vanilla disappears. 

Add flour to the bowl and mix until it forms a dough ball.

Roll the dough until about 1/2" thick, then cut into desired shape. 

Place cookies onto a sheet tray and refrigerate until cold and firm to the touch, about 1 hour.

Preheat oven to 350°F. 

Bake cookies for 20-25 minutes until cookies are lightly golden on the edges. 

Allow to cool before serving.