1. The day before you want banana bread, mix together sourdough starter, melted butter or olive oil, eggs, and flour. Cover well and allow to ferment at room temperature for 6-10 hours. 2. Now, place in the fridge and allow to continue fermenting for another 12-24 hours. (If you don’t have time you can skip or shorten this step, it just means the flour will be less fermented). 3. Once your fermented flour is ready to use, preheat oven to 350 degrees. 4. Using a stand mixer with the paddle attachment, or a whisk, add mashed bananas, brown sugar, vanilla, salt, cinnamon and nutmeg to a mixing bowl. 5. Set on low to medium speed and mix until everything is completely combined. The pre-fermented dough takes a little extra time to be fully incorporated. Once everything is incorporated, sprinkle the baking powder and baking soda on top of the batter, and mix until evenly combined, trying not to over-mix. 6. Butter and flour your pan of choice. 7. For a cake pan, bake 20-35 minutes (depends on size. Check often). For a loaf pan, bake 50-60 minutes. 8. Allow to cool in the pan for one hour before removing and eating. Enjoy and let me know if you have any questions <3