Preheat oven to 375 degrees F (190 degrees C). In a small bowl, stir together flour, baking soda, and baking powder. Set aside.
In a large bowl, cream together the butter and sugar until smooth. Beat in egg and vanilla. Gradually blend in the dry ingredients. Add lavender and stir until just mixed. Wrap in plastic and freeze for 20 minutes.
Roll dough out on floured surface. Cut into desired shapes (I just used a small dish to cut cookies into thick rounds). Place onto ungreased cookie sheets.
Bake 8 to 10 minutes in the preheated oven, or until golden. Let stand on cookie sheet two minutes before removing to cool on wire racks.