Using a stand mixer with the paddle attachment, cream the butter and sugar. Then add the vanilla extract and egg and mix until combined.
Add in the flour and chocolate chips and mix using a wooden spoon until combined.
Roll a heaped teaspoon of biscuit mixture into balls and flatten slightly with the palm of your hand before cooking for 10-12 minutes or until golden brown.
Cool on the tray for 5 minutes before transferring to a wire rack to completely cool.