Sourdough Discard Banana Bread
A moist, deeply banana-flavored loaf with brown sugar and a subtle tang from unfed sourdough discard. It's a quick bread with no rise time, and it uses up discard in one bowl.
- Prep
- 20 min
- Cook
- 1 hr
- Wait
- 1 hr 15 min
- Total
- 2 hr 35 min
- Makes
- 1 loaf (10 slices)
Steps
Before you start
- Use bananas with peels that are heavily speckled or mostly brown. They should be soft and very fragrant.
- Use discard at 100% hydration (equal weights flour and water) that is unfed, 1 to 14 days old, and stirred. Bring it to room temperature if it's been in the fridge, or just let it sit while you prep.
- Let the eggs come to room temperature (about 20 minutes on the counter, or 5 minutes in a bowl of warm tap water) so they don't firm up the melted butter.
- Plan on about 2½ hours start to finish, including a full cool-down so the slices cut cleanly.
Heat oven, prep panOven 350°F / 175°C
- Position a rack in the center of the oven and heat to 350°F (175°C).
- Lightly butter a 9×5-inch (23×13 cm) loaf pan.
- Line the bottom and two long sides with a strip of parchment, leaving a 2-inch overhang on each side to use as handles, and lightly butter the parchment.
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Ready when: Pan is lined with no bare spots on the bottom or long sides.
Tip: Melt the 113 g of butter for the batter now so it has time to cool while you work.
Mash the bananas
- In a large bowl, mash the peeled bananas with a fork or potato masher until mostly smooth with a few small lumps remaining.
- You should have about 1½ cups.
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Ready when: Mash looks like thick, loose puree with pea-sized lumps at most.
Tip: If your bananas are frozen, thaw them fully and use all the liquid that collects.
Whisk in wet ingredients
- Add the melted, slightly cooled butter and the brown sugar to the mashed bananas and whisk for 1 minute until the sugar looks mostly dissolved into a glossy mixture.
- Whisk in the eggs one at a time, then the vanilla, until fully blended.
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Ready when: Mixture is smooth and uniform with no streaks of egg.
Tip: If the butter is still hot, it can scramble the eggs. It should feel barely warm to the touch.
Add the discard
- Add the sourdough discard and whisk for about 30 seconds until it is completely incorporated and no stringy streaks remain.
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Ready when: Batter base looks uniform and slightly thickened.
Combine dry ingredients
- In a medium bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon for 20 seconds until evenly mixed with no clumps of baking soda.
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Ready when: Mixture is a uniform pale tan color.
Tip: Break up any baking soda lumps with the back of a spoon so you don't get bitter pockets.
Fold batter together
- Add the dry mixture to the wet mixture.
- Using a silicone spatula, fold gently, scraping the bottom of the bowl, just until no dry flour streaks remain, about 15 to 20 strokes.
- Fold in the chopped nuts, if using, with the last few strokes.
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Ready when: Batter is thick and lumpy-smooth with no dry flour visible.
Tip: Stop mixing as soon as the flour disappears. Overmixing builds gluten and makes the loaf tough and gummy.
Fill the pan
- Scrape the batter into the prepared pan and spread it into an even layer, nudging it into the corners.
- Sprinkle the top with the turbinado sugar, if using.
- Tap the pan firmly on the counter once or twice to release large air bubbles.
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Ready when: Batter is level and comes about two-thirds up the sides of the pan.
Bake the loafOven 350°F / 175°C
- Bake at 350°F (175°C) for 55 to 65 minutes.
- If the top is deep brown by 40 minutes, loosely tent it with foil.
- The loaf is done when the top is deep golden brown and domed with a crack down the center, a toothpick inserted into the center comes out with a few moist crumbs but no wet batter, and an instant-read thermometer reads 205°F (96°C).
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Ready when: Toothpick shows moist crumbs only, center reads 205°F (96°C), and the top springs back lightly when pressed.
Tip: Check at 55 minutes. If the toothpick shows wet batter, bake in 5-minute increments, since a very ripe, wet banana mash can add time.
Cool in the pan
- Set the pan on a wire rack and let the loaf rest for 15 minutes so it firms up enough to lift out without tearing.
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Ready when: Sides pull slightly from the pan and the loaf feels steady when nudged.
Cool and slice
- Use the parchment handles to lift the loaf out of the pan and set it on the rack.
- Cool for at least 1 hour before slicing with a serrated knife into 10 slices of about ¾ inch (2 cm).
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Ready when: Loaf feels barely warm or at room temperature on the bottom.
Tip: Slicing while hot makes the center gummy and the slices crumble. The flavor also deepens as it cools.
Good to know
Tips
- Weigh the bananas and discard if you can. Banana size varies a lot, and too much banana or a wetter discard makes a gummy center.
- Active, bubbly starter works too, but unfed discard gives a more pronounced tang and no extra lift is needed since baking soda and powder do the leavening.
- Use a light-colored metal pan. Glass or dark pans brown the outside faster, so lower the oven to 325°F (165°C) and bake 5 to 10 minutes longer.
- For a bakery-style crown, run a buttered knife down the center of the batter lengthwise before baking so it splits neatly.
Make ahead
"Bake the loaf up to 1 day ahead. Cool it completely, wrap tightly, and keep at room temperature. The flavor and moisture improve overnight. You can also mix the batter and refrigerate it in the pan for up to 12 hours, then bake straight from the fridge, adding 5 to 10 minutes to the bake time."
Storage & reheating
"Room temperature: wrap tightly or keep in an airtight container for up to 3 days. Refrigerator: up to 1 week in an airtight container, but bring slices to room temperature before eating. Freezer: wrap whole or sliced loaf in plastic and then foil, and freeze up to 3 months. Thaw at room temperature for 2 to 3 hours, or toast frozen slices. Reheat a slice in a 300°F (150°C) oven or toaster oven for 5 to 8 minutes, or microwave for 15 seconds."
Substitutions
- unsalted butter → neutral oil (such as canola or vegetable), 100 ml (⅓ cup plus 1 tbsp). Gives a slightly moister, more tender loaf with a little less buttery flavor. No need to cool it.
- light brown sugar → coconut sugar or dark brown sugar, same weight. Dark brown sugar gives more molasses depth. Coconut sugar gives a slightly drier crumb.
- all-purpose flour → half whole wheat flour (90 g) and half all-purpose flour (90 g). Makes a nuttier, slightly denser loaf. Don't replace more than half.
- walnuts or pecans → dark chocolate chips, 120 g (¾ cup). Fold in at the same time as the nuts. Toss them in 1 tsp of the flour first to keep them from sinking.
