80g walnuts, chopped roughly, plus extra for garnish
Preheat oven to 180°C.
In a bowl, cream the butter and the sugars together. Add the egg and Christmas Cake & Pudding Spice, and beat until it has the consistency of a heavy mousse, then gently knead in flour and baking soda.
When a smooth and thick dough forms, add the walnuts. Pick off pieces of dough, roll them into walnut-sized balls and press half a walnut on top of each ball. Place them on a parchment-lined baking sheet.
Bake for 8 minutes or until the cookie edges are golden.
Once the cookies are completely cool, transfer them to an airtight container and refrigerate them for up to 2 weeks.