Preheat the oven to 350 degrees F.

Lightly grease a 9x5 inch loaf pan with soft butter.

In a large bowl, use a hand mixer to mix together the butter, brown sugar, eggs and mashed banana until well blended.

In a separate bowl, whisk together the flour, baking soda, and salt.

Pour the flour mixture into the banana mixture and use a hand mixer to mix until just blended.

Stir in the chocolate chips if using. Otherwise pour the batter into the prepared loaf pan.

Bake for 60-65 minutes in the preheated oven (23 minutes for the mini loaves, 11 minutes for mini muffins). Loaf is done when a long toothpick inserted in the center of the loaf comes out clean. For a chocolate chip banana loaf you may see melted chocolate on the toothpick which is fine, but you should not see banana batter.

Cool for 10 mins, then take the loaf out of the pan.