The basic recipe calls for the well-soaked beans to be placed in a special pot called damassa with plenty of cold water. Some cooks add a small proportion of split red lentils, which helps to thicken the sauce and improve the colour. Carrot/onion/tomato (alone or mixed) can be added for extra flavour. Those who wish to eat their ful with hard-boiled eggs sometimes add them at this stage. Bicarbonate of soda is another common addition—the bean skins are invariably tough—and (in the Gulf) slices of lemon are sometimes added as well.