I know, you already have a lot of recipes for chocolate cake. Why keep another one? Because it's good, that's why! And because sometime you have the ingredients for one, sometimes for another, and maybe you want a certain texture. I'd call this a basic chocolate cake, not especially dense, not especially light, and well suited for cupcakes, layer cakes, or sheet cakes.
Cream butter, shortening, sugar and vanilla until fluffy; blend in eggs. Combine dry ingredients and mix well. Add alternately with milk to batter. Blend well.
Pour into two greased and floured 9" pans. Bake at 350 for 30 to 35 minutes or until done. Cool 10 minutes in pan, then remove from pan and cool completely before frosting. For cupcakes, cook about 25 minutes. Yum all around.