Collect all the ingredients: Egg (2), Whole Wheat Pastry Flour (370 gram), Vanilla Extract (to taste), Lime (1), Lemon (1), Unsalted Butter (14 tablespoon), and Granulated Sugar (150 gram).
Dice the unsalted butter into cubes, and allow it to soften.
Slice the lemon and lime into thin wheels and remove the seeds.
Place the lemon and lime into the blender. Blend until fine.
Add the white sugar to the softened butter.
Mix the sugar and butter together.
Add the vanilla extract.
Add the blended lemon and lime.
Mix everything until evenly combined and transfer to a clean working surface.
Use the plastic wrap to cover the batter/dough and form it into a log.
Put it into the refrigerator for around 30-60 minutess. Until it holds it shape.
Preheat the oven to 350 degrees F (180 degrees C). Remove the cookie log from the freezer and remove the plastic wrap. Slice 1/4 in. thick cookies and arrange them on a baking sheet.
Bake them for 15 minutes and enjoy!