Sift together flour, baking soda, salt, the three spices and set aside. Mix until blended, the shortening, sugar, molasses and sour milk. To this add the flour mixture, the walnuts, the raisins and citron. Mix until well combined.

Turn dough onto a large sheet of waxed paper or foil. Shape into a roll 2 inches in diameter. Wrap in the paper or foil and refrigerate for several hours or overnight (or even up to two weeks).

About 15 minutes before baking time, turn on oven and pre-heat to 350 degrees F (175 degrees C). Grease cookie sheets.

Slice chilled dough 3/8 inch thick and place on greased cookie sheet. Bake about 15 minutes or until done.