Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment paper.
In a large mixing bowl, combine the mashed bananas, Greek yogurt, eggs, honey (or maple syrup), melted coconut oil, and vanilla extract. Whisk until smooth and well-combined.
In another bowl, whisk together the baking soda, baking powder, salt, ground cinnamon, and all-purpose flour until evenly distributed.
Gradually fold the dry ingredients into the wet ingredients. Mix until just combined; be careful not to over-mix.
If desired, fold in the chopped walnuts or pecans and dark chocolate chips.
Pour the batter into the prepared loaf pan, smoothing the top with a spatula.
Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, remove the bread from the oven and let it cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.
Notes
Slice and serve warm or at room temperature, optionally with a dollop of Greek yogurt and a sprinkle of cinnamon on top.