Pre-heat oven to 150 degrees/gas mark Line two baking trays with greaseproof paper.
Put the sugar; butter; golden syrup; egg and vanilla extract into a large mixing bowl. Mix with an electric mixer on low speed for 3 minutes, until there are only small lumps of butter visible, then turn the speed of the mixer up to medium for 1 minute to reduce the size of the butter lumps.
Sift both types of flour and the mixed spice into the bowl and mix on a low speed for 1 minute, or until combined, then turn the mixer up to medium speed for 30 seconds, or until the dough clings together and the sides of the bowl are clean.
Turn the dough out onto a clean work surface. Divide into two and squash into even flat discs. Cover with cling film and chill or use immediately. Roll out the dough to an even thickness and cut out your biscuit shapes
Carefully pick up each biscuit with a palette knife and place onto the lined trays. Space the biscuits out evenly.
Place the trays into the preheated oven and back for 20 – 30 minutes (check at 20 minutes).
When the biscuits are evenly cooked and just beginning to turn a golden colour, remove from the oven and transfer the whole sheet of greaseproof paper to a cooling rack.