Cointreau biscuits

Mix the butter with the sugar until it becomes a creamy mixture. Add the egg and Cointreau and mix. Add the flour sieving it bit by bit and knead until the mixture is homogeneous. Keep the dough in the fridge 1 hour covered with cling film. Stretch to 5mm and cut the desired shapes. Place the biscuits on the baking sheet and bake at 180º C between 10 and 15 minutes (it is important to preheat the oven).
Note:
Before putting it in the oven, half of the biscuits can be brushed with egg and the rest with powdered sugar.