In a bowl, combine flour, cocoa powder, baking soda, and salt. Mix together.
In the bowl of your mixer, beat together butter, oil, and sugar until light and fluffy.
Evenly distribute batter into 4 pans. Bake pans for about 22-25 minutes or until a knife is inserted and comes out clean.
Cool in pans for 5 minutes, then invert cakes on a wire cooling rack to cool completely.