Prepare a cup of thick sourdough starter the night before. Let sit in a warm spot overnight.
Cream sugar and shortening until light and fluffy. Beat in eggs, one at a time. Stir in sourdough starter, milk, vanilla extract, cinnamon and melted chocolate. Beat with rotary beater 2 minutes. Blend salt and baking soda together until smooth. Sprinkle over batter and fold in gently. Fold in flour until batter is smooth. Pour into 2 (8- or 9-inch) greased and floured pans. Bake at 350° F for 25 minutes. When done, cake will spring back when pressed lightly with fingers and will shrink slightly from sides of pan.
Cool and frost with your favorite frosting.
Servings: 8