Preheat oven to 325 ° F. Grease a 10-inch bundt pan.
In a medium mixing bowl, cream together butter, cream cheese, and sugar.
Add eggs one at a time, beating well after each egg. Add vanilla.
In a separate bowl, combine and sift flour, baking powder, and cocoa.
Add about half of the flour mixture to the butter mixture and beat well. Add remaining flour mixture and beat well (about 2 minutes). You can also do this in your stand mixer with the paddle attachment.
Pour into pan and bake for 1 hour and 15 minutes or until done. Use a toothpick to test at 55 minutes. If the toothpick is removed *mostly* clean, the cake is done.