Cream the butter and the sugar in a mixing bowl. Beat the egg yolk, milk and vanilla essence and add to the mixing bowl.

Fold in the flour and then add desired flavour. You should end up with a slighty sticky dough.

Split mixture into 10/12 for small cookies or 4/5 for Large cookies. Roll into small balls and pat down to form discs. The dough rises very well so space each disc with room to grow.

Pre-heat your oven (375F/190C/GasMark5) and bake cookies for 10/12mins or until golden brown. Place on a cooling rack before eating.