Add the butter, golden syrup, sugar and spices in a pan and simmer gently until the butter has melted and the sugar has dissolved. Remove from the heat and let cool for 5 minutes
Mix in the orange zest, then mix in the bicarbonate of soda, then add the flour and mix into make a soft dough.
Dust with a little flour, then cover in plastic wrap and chill for at least 2 hours.