• 180 g(6½ oz) butter, softened
• 150 g(5½ oz) caster (superfine) sugar
• 1 egg
• 1 teaspoon vanilla extract
• 240 g(8¾ oz) plain (all-purpose) flour
• 20 g(¾ oz) unsweetened cocoa powder

Mash together the butter and sugar in a bowl with a wooden spoon. Add a pinch of salt and all but 20 g(¾ oz) of the flour and work them in. Whisk the egg with the vanilla and add this to the bowl, mixing it all well. Now knead it quickly, gently and thoroughly.

Divide the dough in half. Add the cocoa to one half, kneading it in thoroughly. Knead the remaining 20 g(¾ oz) of flour into the other half. Pat both doughs down into flattish discs, cover separately with plastic wrap and refrigerate for about 30 minutes.

Preheat the oven to 180°C (350°F/Gas 4).

On a lightly floured surface, roll out the doughs separately to a thickness of about a few millimetres, depending on what you decide to make. You can cut out circles, squares and Christmas shapes with a biscuit cutter, cut free-form shapes with a small blunt knife, or make plaits by folding strips of each colour over each other and pressing the ends together. Put on baking trays lined with baking paper, allowing a little room for the biscuits to spread. Bake for 12–15 minutes, or until they are crisp.