Cream the butter and cream cheese together until smooth.
Gradually add sugar and beat until light and fluffy.
Add eggs, one at a time, mixing well after each.
Stir in bananas and vanilla.
In separate bowl, mix flour, cinnamon, baking powder, baking soda and salt. Add to banana mixture and mix until moist. Do not over mix. The batter will thick but very wet.
Pour into prepared pan. Bake for 55 minutes. Check with toothpick or knife and bake a little longer if it doesn't come out clean.