Grease a 10 inch loaf pan and set aide.
Preheat oven 350.
In a mixer, beat butter and both sugars until creamy.
Add eggs.
Add bananas.
Add flour, cocoa, powder, salt, soda until combined.
Add buttermilk until smooth.
Pour half into the loaf pan, top with cream cheese mix, spread rest of batter on top and bake 60 minutes or until puffed and done. Let cool 20 mins in pan. Invert onto a cooling rack to cool completely.