Measure the baking block, brown sugar and golden syrup into a saucepan. Place over medium heat and stir until melted and combined. Allow the mixture to bubble up for a few minutes, then remove from the heat and leave to cool for 10 minutes.
In a separate bowl, whisk the flour, cocoa powder and spices together.
Pour in the butter mixture and fold to make a smooth dough.
Wrap the dough in clingfilm and place in the fridge for 30 minutes.
Preheat the oven to 160°C fan / 180°C conventional and line a large baking sheet with baking paper.
Lightly flour a worktop and rolling pin. Roll the dough out to roughly 0.5cm thickness. Use a 5cm round cutter to stamp out biscuits (you’ll need to reroll the scraps to make 14 in total).
Use a straw or small round piping tip to stamp out a hole at the top of each biscuit.
Transfer to the baking sheet and bake for 12 minutes until firm around the edges. If the holes have closed up during baking, use a straw to make another hole whilst the biscuits are warm. Leave to cool.