Preheat oven to 350 degrees F.

Grease and flour bundt pan: Use a pastry brush to spread a very thin, even layer of shortening all over the inside of the bundt pan. Add a pinch of flour and dust it over the pan. Hold the pan over the sink and tap it hard, in a circular motion, all around the edges so the flour lightly covers the inside of the pan.

Combine dry ingredients in a bowl: flour, baking powder, baking soda, and salt.

In a separate bowl, cream together the butter and brown sugar, using electric hand mixers or a stand mixer, until light and fluffy. Mix in the eggs and vanilla. Mix in the buttermilk and mashed bananas.

Add the dry ingredients, stirring gently, just until combined.

Bake: Pour into the prepared bundt pan and bake for 45-55 minutes or until a toothpick inserted comes out clean.

Allow to cool for a few minutes before inverting onto a cooling rack. Cool completely before frosting.

Cream butter and cream cheese together until smooth and fluffy. Add powdered sugar and mix for several minutes, until fluffy. Add more powdered sugar, if needed.