Cream sugar and shortening. Add eggs, one at a time, and beat well.
Sift together flour, cocoa and salt. Add dry ingredients alternately with buttermilk or sour milk. Beat until smooth.
Dissolve baking soda in boiling water and add last. Mix until well blended.
Bake in three layers or a large loaf pan at 350 degrees, about 40 minutes for layers and an hour for loaf. This cake batter is quite thin. It makes a large, moist, delicious cake.