In a small bowl beat slightly the egg yolks, whole egg, zest, and vanilla.

In a large bowl add the flour, make a well in the middle and add the butter, sugar, salt and egg mixture. With a fork mix until almost combined, then move to a lightly floured flat surface. Knead gently to combine (don't over knead). Dough will be soft. Wrap in plastic and refrigerate one hour.

Pre-heat oven to 400 F (200 C). Line 2 cookie sheets with parchment paper.

Remove dough from the fridge and break off small pieces of dough, soften the dough slightly between your finger and roll into approximately 4-6 inches, form into an S shape. Place on prepared cookie sheets and bake for 10 minutes, reduce heat to 320F (150C) and bake for another 10-15 minutes or until lightly golden. Let cool completely before serving. Enjoy.