In a large bowl beat butter with a mixer on medium to high 30 seconds. Add granulated sugar, baking powder, baking soda, and salt. Beat until combined, scraping bowl as needed. Beat in sour cream, egg, 1 1/2 tsp. of the vanilla, and, if desired, lemon zest. Beat in flour. Divide dough into four portions. Cover and chill 2 hours or until dough is easy to handle.