Preheat oven to 375 degrees. Butter a baking pan (the original recipes call for an 8 inch square pan. For some reason, I chose to use an 11 by 7 inch pan. They hold the same capacity, so use whatever one you’d like).
In a large bowl, mash the bananas. Break in the eggs and stir to combine. Add flour, sugar, baking soda, cinnamon and vanilla extract and mix. When the batter has formed, add the chocolate chips and stir to incorporate.
Scrap the batter into your baking dish and bake for 30-40 minutes. Mine was done at the 32 minute mark, but I used a dark metal baking pan, which tends to make things brown faster than glass. It is done when the top is burnished and a toothpick comes out clean (save streaks of chocolate chip).
It is wonderful eaten warm, but remains amazingly tasty eaten out of a gladware container, four days later.