Prepare the baking sheet, by lining with the baking paper or Silpat.
Stir together the flour, sugar, baking powder, sesame seed and salt. On low speed, sitr in the butter and shortening a little at a time until the mixture resembles coarse crumbs.
In a medium bowl, whisk the egg, vanilla and lemon zest. Stir the egg mixture into the dry ingredients until smooth and well blended, about 2 minutes. Cover the dough with plastic wrap and refrigerate 1 hr.
Roll the dough into 0.5 cm thin then cut with the cookie cutter. Place the cookies on the baking sheet. Continue with the remaining dough, placing the cookies 1 inch apart.
