Preheat the oven to 160ºC. Line the baking sheets with unbleached parchment paper and set them aside.
In a large bowl, mix the flour, arrowroot, baking powder, cinnamon, ginger, salt and granulated sugar and whisk to combine well.
Add the brown sugar. Whisk to work out the lumps in the brown sugar.
Create a well in the centre of the dry ingredients and add the black treacle, honey, vanilla, butter and egg, mixing to combine after each addition. The dough will be thick, smooth and somewhat sticky to touch.
Transfer the dough to a large sheet of unbleached parchment paper. Cover with another sheet of parchment and roll into a rectangle about a third of an inch thick.
Dip a gingerbread man cutter in all-purpose gluten-free flour and use it to cut shapes from the cookie dough.
Place the gingerbread men around 1 1/2 inches apart on the prepared baking sheets. Gather and re-roll the scraps until all the dough has been used.
Place the cut-outs on the baking sheets in the fridge or freezer until firm (around 20 minutes in the fridge or 5 in the freezer). Place in the centre of a pre-heated oven and bake until dry to the touch (around 15 minutes).
Remove from the oven and allow to cool completely on the baking sheets. They will crisp as they cool. You can then either eat them plain or decorate with icing.