Preheat the oven to 180°C (160°C fan), gas mark 4.
Line two flat baking trays with non-stick parchment.
Cream together the butter and sugar, then gradually beat in the egg and vanilla extract.
Sift and stir in the flour and cocoa powder and mix to a fairly soft dough.
Turn onto a lightly floured surface and knead gently. Cover or wrap the dough in cling film and chill for at least 30-60 minutes.
When ready, roll the dough out on a lightly floured surface to around the thickness of 0.5cm.
Cut into moustaches using either the cut out template or appropriate shaped cutter.
Carefully transfer the biscuits to the lined baking sheets using a spatula and carefully poke a coffee stirrer stick up into the bottom of each biscuit. Repeat with the remaining dough, and re-roll the trimmings to make more biscuits. Note: you may need to use more trays or bake the biscuits in batches due to the coffee stirrer sticks taking up room on the trays.
Bake the biscuits for approximately 10-12 minutes. Leave the biscuits to firm up on their trays before transferring to a wire rack to cool.
If adding an extra chocolate flourish to your moustaches, apply the melted chocolate to the front of each biscuit using a paintbrush and sprinkle with chocolate strands for even more chocolate taste and texture.