Pre-heat oven to 325.
Add 12 tbsp of butter to a sauce pan with ¾ a cup cocoa, stirring occasionally over low heat. Once smooth, take off the heat and let cool.
While the butter and cocoa is cooling, add 1 cup of brown sugar, ¾ a cup of cane sugar, ¾ a cup of flour, and a large pinch of salt to a bowl.
Once the butter and cocoa have cooled, pour the mixture into a mixing bowl. Then whisk in 2 eggs and 1 ½ bananas, along with 1 teaspoon of vanilla. The banana will incorporate when whisked, but I like to try and leave some chunks still intact. It’s best to use a ripe banana for this because they are softer.
After the binders have been added to the cocoa mixture, add the dry ingredients. Stir all the ingredients together until homogeneous. Then transfer to a buttered 8 by 8 square pan, baking for about 50 minutes.
Let cool then cut.