* More Baking Soda may be added if the starter if very sour. Place flour in bowl, add starter in a well, then add melted shortening and dry ingredients. Mix lightly and turn out onto a lightly floured board and knead until the consistency of bread dough, or of a satiny finish. Pat or roll out dough to 1 cm thickness, cut and put on a greased pan. Coat all sides of biscuits with melted butter. Let rise over boiling water for half hour. Bake at 220ºC for 15 to 20 minutes.