Preheat oven to 325 degrees
Combine butter and cream cheese together until smooth.
Add sugar and combine well.
Add eggs one at a time; be sure each egg is completely incorporated before adding the next egg.
Add cake flour one cup at a time, fold in flour being careful not to over mix.
Pour cake batter into a well-greased/well-sprayed bundt cake pan.
Bake for approximately 90 minutes, until a toothpick inserted comes back clean.
Remove from oven and allow the cake to cool for approximately 10 - 15 minutes before removing from the cake pan.