Preheat the oven to 200°C/180°C fan/gas mark 6.
Place all the ingredients into a mixing bowl and using a spatula, mix well until a dough forms.
Rest for 5 minutes.
Using a rolling pin, roll the dough out onto a clean dusted surface, to form a 20cm square.
Slice the square down the middle and slice each half of the dough horizontally into 5 equal rectangle shortbreads.
Prick holes in the top of the shortbreads and place on a lined baking tray.
Bake in the oven for 15 minutes or until golden.
Sprinkle with the extra sugar and allow to cool on a wire rack.
Fate Low Protein All-Purpose Mix is a food for special medical purposes and must be used under medical supervision. This recipe has been specifically designed for a low protein diet. Refer to labels for allergen and other product information.