Preheat oven to 400 degrees F. In a large bowl, combine flour, baking powder, baking soda, sugar, salt, zest, and lavender. Cut in butter until mixture resembles cornmeal. Stir in egg and buttermilk with a fork. Turn dough onto a floured board and knead gently but briefly (don’t overknead). Divide in half and pat each piece into a ¾-inch-thick round. Cut each round into six wedges and place them 1 inch apart on an ungreased baking sheet. Bake for 20 minutes, or until golden. Serve hot or at room temperature.