Whisk the flour, xanthan gum if using, cocoa powder and baking soda together
Cut in the butter to form a breadcrumb mixture then mix in the sugar
Add the vanilla and enough milk to form a soft dough
Wrap and let chill in the fridge for 1 hour.
Let the dough rest out of the fridge for 20 minutes then flour a surface and roll out to around 5mm thick
Cut out the cookie shapes using a 2.5 cm cutter. Place back on the parchment paper-lined baking sheet. Re-roll scraps and repeat. Put back into the fridge for 20 minutes to chill again. This will stop the shapes spreading when baked
Meanwhile, preheat the oven to gas 4 / 180C / 350F
Bake the cookies for 12 - 16 minutes or until the center of the cookie no longer looks wet and they've risen slightly
Let cool on a wire rack
Follow my Royal Icing recipe to make the thick cookie glaze. Ice as shown. Cut some holly leaves from some green ready roll icing and roll some berries from some red to complete the topping decoration
