Preheat your oven to 350 degrees F. Greese your 9x5 loaf pan really well to ensure the bread doesn't stick. You could also flour the pan or put parchment paper on the bottom of the pan.
In a medium sized bowl mix together the flour, baking powder, baking soda, cinnamon and salt. Set this bowl aside.
In a large bowl beat together the butter and the sugar. Beat these ingredients until light and fluffy. Add your eggs one at a time to make sure they incorporate well in the batter.
Beat in the mashed banana, buttermilk and vanilla extract to the egg/butter/sugar mixture.
Take your dry ingredients and fold it into the wet ingredients. I do a little at a time to make sure everything is incorporated. Once everything is mixed together (don't overmix), fold in the mini chocolate chips.
Pour the batter into your prepared pan. Bake the bread for 50-60 minutes or until a toothpick inserted in the center of the bread comes out clean.
Let the bread cool in the pan for 15 minutes before transferring to a wire rack to cool.