In a bowl, place the butter and flour and mix with your hands until you reach a sand like consistency
Add the powdered sugar, vanilla, egg, zest, and mix with your hands until the dough can hold shape
Knead into a ball, wrap in plastic foil and chill in fridge for 30 mins minimum
Once chilled, get two baking sheets and roll the dough between them (2cm thickness)
Cut out shape of choice, making sure you have an even number of cookies
Leave half cookies as is and the rest make a hole in the middle
Bake in a preheated oven at 180 for around 10 mins or until they slightly change color, do not overbake so they don't get crunchy
Once cooled, add jam on the biscuits without a hole and cover it with the biscuit that has a hole
Sprinkle powdered sugar on top and serve