Pre-heat the oven to 180C/Fan 160/Gas4
Line two baking trays with baking paper.
In a large mixing bowl cream together the butter & sugars then stir in the vanilla & beat in the egg lightly.
Sift in the flour & add the chocolate chips. Stir until combined.
Take walnut sized pieces of the dough, roll into balls & place on the baking tray making sure you allow enough room in between as they will spread out.

Bake for 5-10 minutes or until the cookies are golden around the edges.
Remove from the oven & leave on the tray for a few minutes to firm up then transfer to a wire rack to cool.
Keep in an airtight container but I doubt they will last long....actually, hide them....& don't tell anyone where they are...!