This is the way most cakes were baked in Alaska in the early days before baking powder became more common.
1 cup thick sourdough starter
1 cup granulated sugar
1/2 cup shortening
1 cup evaporated milk
1 teaspoon vanilla extract
1 teaspoon ground cinnamon
3 (1 ounce) squares semisweet chocolate
1/2 teaspoon salt
1 1/2 teaspoons baking soda
2 cups sifted all-purpose flour
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 degrees 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.