Preheat the oven to 180 degrees C. Remove the centre oven rack and place a sheet of baking paperon top.
In a mixing bowl, combine the flour, sugar, bicarb, ground ginger and cardamom. Cut in the butter and rub with the fingers until the mixture resembles breadcrumbs. Add the grated ginger, egg and molasses then mix until a stiff dough forms.
Turn out the dough onto a lightly floured work surface and roll to a thickness of 6mm with a rolling pin. Cut out the biscuits using biscuit cutters of your choice and arrange the biscuits on the baking paper. Place the middle shelf grate and biscuits into the oven.
Bake in the preheated oven for 12 to 15 minutes or until firm to the touch and a nice brown colour. Remove from the oven and allow to cool fully on a wire rack before enjoying, about 30 minutes.