Sourdough Discard Banana Bread
This sourdough discard banana bread recipe takes overripe bananas and unfed starter and turns them into a moist, lightly tangy loaf that stays soft for days. The discard adds gentle acidity that brightens the sweetness of the bananas and creates an extra-tender crumb.
Equipment
- 9x5-inch loaf pan - light-colored aluminized steel recommended
- Large mixing bowl
- Medium mixing bowl
- Fork or potato masher - for mashing bananas
- Rubber spatula
- Kitchen scale - recommended for accuracy
- Whisk
- Measuring cups and spoons
- Wire cooling rack
- Toothpick or cake tester
Ingredients
- 3 large overripe bananas - about 1½ cups or 340g mashed, deeply brown and very soft
- ½ cup unsalted butter - 113g, melted and slightly cooled
- ¾ cup packed brown sugar - 150g, light or dark both work
- 2 large eggs - room temperature
- ½ cup sourdough discard - 120g, unfed, straight from the fridge is fine
- 1 teaspoon pure vanilla extract
- 1½ cups all-purpose flour - 190g
- 1 teaspoon baking soda
- ½ teaspoon baking powder
- ½ teaspoon fine salt
- 1 teaspoon ground cinnamon
- ½ cup chopped walnuts or pecans - 60g, optional but recommended
Instructions
- Preheat oven to 350°F (175°C). Grease a 9x5 inch loaf pan with butter or non-stick spray. For easy removal, line with a parchment paper sling.
- Melt butter in microwave in 30-second intervals or on the stovetop over low heat. Let cool for at least 5 minutes.
- Peel bananas and mash thoroughly in a large bowl with a fork or potato masher until mostly smooth with a few small lumps remaining.
- Add brown sugar, eggs, cooled melted butter, sourdough discard, and vanilla to the mashed bananas. Mix with a spatula or whisk until smooth and cohesive.
- In a separate medium bowl, whisk together flour, baking soda, baking powder, salt, and cinnamon until evenly distributed.
- Pour dry ingredients into the wet ingredients all at once. Fold gently with a spatula until just combined and no dry streaks remain. Do not overmix.
- Fold in walnuts or chocolate chips with 3 to 4 gentle strokes. Reserve a small handful to sprinkle on top before baking.
- Pour batter into the prepared pan and spread evenly. Tap the pan on the counter 2-3 times to release air bubbles.
- Bake on the center rack for 55 to 65 minutes. Check doneness by inserting a toothpick into the center — it should come out clean or with a few moist crumbs. Tent with foil if browning too quickly.
- Cool in the pan for 15 minutes, then use the parchment sling to lift the loaf onto a wire rack. Cool for at least another 30 minutes before slicing.
Notes
- Ripen bananas quickly: Place unpeeled bananas on a baking sheet and bake at 300°F (150°C) for 15-20 minutes until skins are black. Cool completely before mashing.
- Measure flour correctly: Spoon flour into your measuring cup and level off with a straight edge. Scooping directly from the bag packs too much flour and results in a dry loaf.
- Don't overmix: Once flour is added, mix only until just combined. Overworking the batter develops gluten and creates a dense, tough loaf.
- Room temperature eggs: Cold eggs can cause melted butter to seize. Take them out 20 minutes before starting.
- Discard age matters: Discard that's been in the fridge for up to two weeks works perfectly. Older discard adds more pronounced tang.
- Check early: Start testing for doneness at 50 minutes since oven temperatures vary and banana moisture affects baking time.
- Storage: Keep at room temperature wrapped tightly for up to 4 days. Freeze individual slices for up to 3 months.
- Reheating: Toast slices in a toaster or warm in the oven at 300°F (150°C) for about 8 minutes for best texture.
- Add-ins: Feel free to swap walnuts for semi-sweet chocolate chips, create a streusel topping, or swirl in peanut butter or Nutella.