Grease a 10-inch cast-iron skillet with olive oil and set aside.
In a large mixing bowl, whisk together flour, cocoa, light brown sugar, baking soda, cinnamon, nutmeg, and salt.
In a separate mixing bowl, whisk together olive oil, eggs, mashed bananas, yogurt, and vanilla.
Pour the banana mixture into the flour mixture and fold with a spatula until just combined.
If using, fold in the chocolate chips and nuts.
Transfer the batter into previously prepared skillet.
Place sliced bananas on top of batter.
Bake for 30 to 35 minutes or until a toothpick inserted into the center of the bread comes out clean.
Let cool in skillet for 30 minutes; cut and serve.
Notes
You can also use a loaf pan to make this banana bread, but the baking time will be about 50 to 55 minutes. Let bread cool in the loaf pan for 10 minutes, then invert it onto a cooling rack and cool completely before cutting.Nutrition Facts does not include chocolate chips and nuts.Adapted from: Food52