Pre-heat oven at 350ºF.

1.- Sift the flour, set it aside.

2.- Sift the powdered sugar, set it aside.

3.- Add the butter to your mixing bowl and start mixing at medium speed for 1 minute. Gradually add the powdered sugar and increase the speed to medium and mix for about 4-5 minutes until it is light and fluffy .

4.-In a small bowl mix the the egg yolk with the zest ( orange/limes) and the vanilla extract. Set aside.

5.- When your mix of butter and sugar is ready add the mix of step 4 and continue mixing at the same speed until everything is well incorporated.

6.- At the lowest speed add the flour in two or three additions, mix for 1-2 minutes until a ball has formed.

7.- Roll out the cookie dough and refrigerate.

8.- Cut out the shapes, place them over the prepared baking trays and bake for 10-13 minutes until the edges starts to golden. When you bake these cookies you need to let them cool down for a little bit in the baking sheet so they harden a little bit and then move them to a cooling rack, like they are so soft they are more fragile when they are freshly baked.

9.- Transfer them to a cooling rack.

Enjoy!