Preheat the oven to 180°c
Add the Butter to a large glass mixing bowl, microwave for a few seconds until the butter has melted
Stir in The Sugar, Egg Yolks, Vanilla Extract and green Food Colouring. You judge how green you would like your cookies, bear in mind they may lighten during baking (see the video below )
Stir in the flour a little at a time. Add the Bicarbonate of Soda and salt, stir well until no traces of Flour can be seen.
Fill a saucer with granulated sugar
Scoop a tablespoon of Cookie dough, roll into a ball, then roll in the Sugar.
Space the Cookie dough balls evenly on a lined baking tray. Press in the Red and Green Smarties
Bake for 8-10 minutes, until cracks form on the surface of the cookie