Sift the flour, baking cocoa, baking powder and salt into a bowl.
Cream the butter and sugar in a mixing bowl until light and fluffy.
Add the eggs 1 at a time, beating well after each addition.
Add the sifted dry ingredients and milk alternately, mixing well after each addition.
Beat in the shortening.
Pour into a well greased tube pan.
Bake at 325 degrees for 1 hour and 15 minutes.
Invert onto a serving plate.
Frost the cooled cake with Cocoa Frosting.