In a stand-alone mixer with the paddle attachment, beat the butter at medium-high speed until smooth. Then add the sugar, vanilla extract, and beat until creamy. (Don't beat until fluffy).
In a separate bowl, mix the flour, xanthan gum, and salt.
Slowly add the dry ingredients to the wet ingredients. Keep beating the dough until all the ingredients are combined, and the dough is crumbly.
If the dough is too crumbly and cannot be shaped into four separate balls, add 4 tablespoon of Milk/Water and mix at low speed until combined.
Now divide the dough into four separate balls.
Afterward, roll one of the dough balls flat (4 mm thickness) and shape your cookies.
Place the shortbread cookies a few centimeters apart on a baking tray lined with baking paper.
Repeat steps 6 to 7 until you are out of dough.
Chill the shortbread cookies in the fridge for at least 30 minutes (Optional)
Preheat the oven to 180° degree celsius.
Remove the shortbread cookies from the fridge and bake them for 10-12 minutes or until the edges are golden brown.
Allow the cookies to cool to room temperature before decorating or serving.