In the bowl of an electric stand mixer* fitted with the paddle attachment cream butter, brown sugar, sugar and vanilla and medium speed until light and fluffy, about 4 to 5 minutes. Scrape down the sides and bottom of the bowl. Add in the eggs and mix for 1 minute more or until well combined. Then the cocoa powder, mixing until smooth. Add in the mashed bananas, baking powder, baking soda and salt and mix on low until completely blended.
If using a mixer, take the bowl out and gently fold in the flour until barely combined. Dump in the hot water and whisk to combine. Scrape the sides and bottom of the bowl to make sure the banana bread batter is well combined. Set aside for 10 to 20 minutes while you preheat your oven.
Preheat your oven to 350℉ (177℃). Grease a 9 x 5-inches (23 x 13-cm) loaf pan (see loaf pan notes above the recipe) and line with parchment paper letting the excess fall over the two longer sides of the pan.
Pour the banana bread batter into the prepared pan, sprinkle with chocolate chips and bake in the center of the oven for 60 minutes or until the edges are set and the middle of the cake is puffed up and (probably) cracked.
Let sit for 10 minutes on a cooling rack and then use the parchment overhang to pull the bread out of the pan and let finish cooling on the rack. I think it's most delicious slightly warm or at room temperature (not hot).