Preheat oven to 180°C and line a 12 hole cupcake tin with cupcake cases.
To a large bowl add caster sugar, flour, baking powder, xanthan gum, cocoa powder and salt. Mix well until combined.
To a separate bowl whisk dairy free milk, eggs, vanilla extract and melted butter. Combine the wet and dry ingredients and then add the hot coffee and mix well.
Pour the mixture into the 12 cupcake cases and bake for 20 minutes, or until a skewer comes out clean and leave to cool.
Once cool use a serrated knife to cut a circular hole in the top of each cupcake. Fill each of the holes with a spoonful of dairy free chocolate spread.
Make the buttercream by beating butter with an electric whisk until soft. Gradually add icing sugar and beat for up to 5 minutes until combined and creamy. Add the vanilla extract and dairy free milk and beat again.
Pipe the buttercream onto the cupcakes and top with mini marshmallows, a dusting of cocoa powder and a candy cane. Store in an airtight container for up to 3 days.