Preheat the oven to 180°C (160°C Fan, Gas Mark 4). Line 2 large baking trays with baking parchment.

In a mixing bowl, beat the butter with the sugar until creamy and well blended.

Sift the flour and cocoa on top and carefully mix all the ingredients together until well combined. Using your hands, bring the mixture together to form a firm dough.

Turn on to a lightly floured surface and knead gently until smooth. Divide the mixture in half. Working with one half of the dough at a time – the mixture will be quite short – roll out to a thickness of ½ cm (1/4 inch). Stamp out 8 x 8cm (3 ¼ inch) skull shapes, re-rolling the dough as necessary. Roll out the other half of dough, with the trimmings, in the same way, and cut out 10 x 7cm (2 ¾ inch) pumpkin shapes, re-rolling the dough as necessary.

Carefully cut out eyes and mouths from half the pumpkins and half the skulls using small cutters or the tip of a sharp knife. Make them slightly bigger than looks natural because the mixture will close in on itself as it bakes. Transfer all the shapes to a baking tray and chill for 30 minutes to firm up.

Bake in the oven for 18-20 minutes until firm. Cool for 10 minutes before transferring to a wire rack to cool completely.

To decorate, put the butter in a bowl and gradually sieve and mix the icing sugar into the butter to make a smooth, creamy icing. Mix in a few drops of Madagascan Vanilla Extract. Divide into 3 equal portions.

Add drops of the 3 different Gel Food Colours to the 3 portions to make vibrant shades. As a guide, you will need approx. 45 drops Red, 70 drops Green, and 75 drops Orange.

Spread a little of the icing over the uncut shortbread pumpkins and skulls and top with a cut shortbread. Press down gently to squeeze the icing carefully into the features.

Once you've sandwiched all the cookies together, they are ready to serve and enjoy!