1. Preheat your oven to 350 F (175 C). Grease and flour a 9×5-inch loaf pan, or line it with parchment paper for easy removal.

2. In a medium bowl, whisk together the all-purpose flour, baking soda, salt, and ground cinnamon (if using). Make sure there are no lumps and the ingredients are evenly distributed.

3. In a large mixing bowl, cream together the softened butter and granulated sugar until the mixture is light and fluffy. This usually takes about 2-3 minutes with an electric mixer.

4. Beat in the large egg until fully incorporated, then stir in the vanilla extract. The mixture should be smooth and well combined.

5. Gently fold in the ripe sourdough discard and the mashed bananas. Mix until just combined; overmixing at this stage can lead to a tougher bread. A few small lumps of banana are perfectly fine.

6. Gradually add the dry ingredient mixture to the wet ingredients, mixing only until just combined. Be careful not to overmix; stop as soon as you no longer see streaks of flour. If using, fold in the chopped nuts and/or chocolate chips.

7. Pour the batter into your prepared loaf pan and spread it evenly. Bake for 50-60 minutes, or until a wooden skewer or toothpick inserted into the center comes out clean. The top should be golden brown.

8. Once baked, remove the loaf from the oven and let it cool in the pan for about 10-15 minutes before transferring it to a wire rack to cool completely. Slicing it while warm is tempting, but a fully cooled loaf will slice more cleanly.