3/4 cup Brown sugar I use dark here; either light or dark work
1 Large egg
1 tsp Vanilla extract pure
1 tsp Baking soda
1/4 tsp Table salt
1/2 tsp Ground cinnamon optional; I skip it
1 cup All-purpose flour
1/2 cup Dutch-process cocoa powder
1 cup Semisweet or bittersweet chocolate chunks or chips about 6 ounces or 170 grams
Equipment
Oven
Loaf Pan
Strainer
Directions
Heat your oven to 350°F. Butter a 9×5-inch loaf pan, or spray it with a nonstick baking spray.
Mash bananas in the bottom of a large bowl. (You’ll have a little over 1 cup mashed banana total.)
Whisk in melted butter, then brown sugar, egg, and vanilla.
Place baking soda, salt, cinnamon (if using), flour and cocoa powder in a sifter or fine-mesh strainer and sift over wet ingredients.
Stir dry and wet ingredients with a spoon until just combined. Stir in chocolate chunks or chips.
Pour into prepared pan and bake 55 to 65 minutes, until a tester or toothpick inserted into the center of the cake comes out batter-free. (A melted chocolate chip smear is expected, however.)
Cool in pan for 10 to 15 minutes, then run a knife around the edge and invert it out onto a cooling rack. Serve warm or at room temperature.