Slice of Spice Cookies

3 cups sifted flour
1 tsp. soda
1 tsp. cream of tartar
1/2 tsp. salt
1/2 cup butter
1/2 cup shortening
2 cups firmly packed brown sugar
2 unbeaten eggs
1 tsp. vanilla
1 cup quick-cooking rolled oats
quilted aluminum foil

Topping:
1/2 cup sugar
4 tsp. cinnamon

Sift flour, soda, cream of tartar and salt. Cream butter and shortening. Gradually add brown sugar, creaming well. Blend in eggs and vanilla. Stir in dry ingredients. Add rolled oats, mix well. Chill 1 hour for easy handling. Divide dough into 3 parts, shape into rolls 12 inches long. Wrap in foil, chill overnight. Cut into 1/4 inch slices; dip into sugar-cinnamon topping to coat both sides. Place on greased baking sheets. Bake at 350 degreees for 9 to 12 minutes until golden brown.