Preheat your oven to 180° C (350° F). Grease a bread pan with butter.
In a large mixing bowl, add the flour, baking soda, salt, and cinnamon. Whisk together. Add the chocolate chips and mix in with a spoon. Set aside.
In another mixing bowl, stir together the melted butter and both sugars. Mix in eggs and vanilla. Mix in the mashed banana.
Add the dry ingredients to the wet ingredients and mix together until just combined to make the batter, do not overmix.
Pour batter into the prepared loaf pan. Optional, top with the additional ½ cup of chocolate chips, along the center of the loaf.
Place in the oven and bake for 50-60 minutes, checking at 50 minutes with a toothpick inserted in the center of the loaf. If the toothpick comes out clean, it is done. Cool on a wire rack 5 minutes. The toothpick may come out with chocolate, it is wet batter you are looking for.
After 5 minutes, run a butter knife along the edges of the loaf, it will be lose. Gently turn out the loaf and allow the loaf to cool completely.
Slice, and enjoy!