Heat oven to 350°F. Grease a 9x5-inch bread pan generously, then lightly dust it with flour or cocoa powder and set aside. Alternatively, line the pan with parchment paper, leaving an overhang for easy removal. For coconut oil preparation, melt the coconut oil, then measure it in liquid form and allow it to cool slightly to prevent cooking the egg.
In a large bowl, whisk 1 large egg with a fork. Add in the vanilla Greek yogurt, cooled coconut oil, vanilla extract, and sugar.
Mash 2–3 overripe bananas until they reach a thick applesauce consistency. Measure to ensure you have 1 full leveled cup. Add the mashed bananas to the wet ingredients and mix until well combined.
Put old-fashioned or quick oats in a blender or food processor and pulse until they resemble flour. Measure after blending to get a leveled 1/3 cup.
In a separate bowl, add oat flour, salt, baking soda, flour, cocoa powder, regular and mini chocolate chips. Stir to combine.
Add the dry ingredients to the wet ingredients and mix gently until just combined, as overmixing will result in denser bread. Use a spatula to scrape all the mixture into the prepared pan. If desired, sprinkle 1 tablespoon of sugar on top for a nice crust.
Bake in the preheated oven for 50–65 minutes, or until a fork or toothpick inserted into the center comes out clean or with a few moist crumbs and the bread starts to pull away from the edges. I recommend checking at 50 minutes. If the top is browning too quickly, tent it with aluminum foil.
Remove the bread from the oven and let it cool in the pan for 15 minutes. Then, transfer it to a cooling rack to cool completely before slicing, as it can be crumbly when fresh out of the oven. Use a very sharp serrated knife for cutting.
Video
Notes
Note 1: Any Dutch-process cocoa works well. If you don’t use Ducth-process cocoa, the bread can turn out fairly dry. Storage: This bread can be stored at room temperature for 1–2 days tightly wrapped or in an airtight container. After 3–4 days, it may be more prone to mold due to its moistness. To warm refrigerated slices, microwave for 5–10 seconds. For longer storage, freeze individual slices wrapped in plastic and placed in a zip-top bag for up to 3 months. To thaw, leave wrapped slices at room temperature for about an hour.