Preheat the oven to 200C/180C Fan/Gas 6. Line 2/3 large baking sheets.
In a large bowl, or the bowl of a stand mixer, combine the dry ingredients (flour, baking powder, baking soda, ground ginger, mixed spice and sugar).
Put the golden syrup in a microwave safe bowl and heat for 20 seconds (it becomes really runny). Pour this and the butter into the bowl. Mix with an electric mixer on high until it looks grainy (but will hold a ball when pressed).
Chop the crystallised ginger into small pieces and add to the dough.
Scoop tbsp sized balls of the mixture, roll into a log/oval shape and lay out on the cookie trays (at least 2 inches apart). Bake for 10-12 minutes, until golden brown.