Preheat oven to 350F. Grease or spray a 9 x 5 inch loaf pan, set aside.
In a large bowl whisk together the melted butter, and sugars. Add the eggs, bananas, vanilla and buttermilk; whisk until smooth.
Sprinkle the flour, baking soda and salt over the butter mixture and stir to mix until just combined. Fold in the mini chocolate chips.