Preheat oven to 180ºC / 160ºC Fan / 350ºF / Gas 4
Cream the sugar, butter, golden syrup and egg in a large bowl. This can be done in an electric mixer using the paddle attachment or by hand with a wooden spoon.
Sift the flour and cocoa powder into the bowl and slowly mix to begin with then increase the speed to medium or mix vigorously by hand for 30 seconds. The dough is ready when it clings together and the sides of the bowl are clean.
Transfer the dough to a lightly floured board and knead it until it forms a smooth ball. Take care not to overwork the dough.
Wrap the dough in clingfilm and chill it in the fridge for 30 minutes.
Once the dough has chilled, roll it out to a thickness of 4-5mm. I find it easier to work in batches as opposed to rolling the dough out all in one go.
Cut into your desired biscuit shapes and transfer to a baking sheet leaving a 2cm space between each biscuit.
Bake in the preheated oven for 20 minutes. Bear in mind that smaller biscuits will bake quicker than larger ones.
The biscuits are cooked when they are browning at the edges and underneath.
Remove from the oven and transfer to a wire rack. Leave to completely cool and firm up before you attempt to decorate.