To the juice and rind of 1 orange, add butter or margarine and enough boiling water to equal 3/4 cup of liquid. Let cool. Add dry ingredients. Add slightly beaten egg. Mix well. In a separate bowl, mix cranberries, walnuts, and flour. Add to above batter. Mix well, batter will be lumpy and stiff. Bake at 350 degrees in a greased pan for 1 hour or until pick in center comes out clean.