Preheat oven to 350 degrees F (175 degrees C). Grease and flour 2 (8 inch) loaf pans. Sift together the flour, cocoa and baking powder. Set aside.
In a large bowl, cream together the butter, shortening and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Beat in the flour mixture alternately with the milk, mixing just until incorporated.
Pour batter into prepared pans.
Bake in the preheated oven for 75 to 90 minutes, or until a toothpick inserted into the center of the cake comes out clean.
Let cool in pan for 10 minutes, then turn out onto a wire rack and cool completely.
