Combine the flour, egg replacer, ¼ cup icing sugar, baking soda and salt. Set aside.
Cream together the butter, 4 tablespoons icing sugar and pandan extract. Add the butter mixture to the flour mixture and combine quickly with cold hands. If you need to add 1 tablespoon water to bring the dough together then do so.
Wrap the Hulk looking dough in cling film (plastic wrap) and place in the fridge for 30 minutes. Cram as many chocolate buttons into your mouth as you possibly can.
Grease and line baking trays then roll your dough into 1 inch-sized balls and flatten them slightly. Arrange the dough balls on your tray evenly spaced (they will spread as they cook).
Bake at 160 degrees C (gas mark 4) for 8-10 minutes then remove from the oven. Make thumbrints in the centre of the half-cooked biscuits with a spoon.
Remove the biscuits from the oven and push in a little chocolate button or a couple of chocolate chips into the thumbprint. Allow to cool thoroughly before taking them off the baking sheet.