Sourdough Discard Banana Nut (Printable Version)

Moist banana loaf with sourdough discard, toasted walnuts and a crisp brown sugar topping.

# Needed Ingredients:

→ Wet Ingredients

01 - 1 cup mashed ripe bananas (about 2 large bananas)
02 - 1/2 cup sourdough discard at room temperature
03 - 1/2 cup unsalted butter, melted and cooled
04 - 2 large eggs at room temperature
05 - 1/2 cup whole milk at room temperature
06 - 1 teaspoon vanilla extract

→ Dry Ingredients

07 - 1 3/4 cups all-purpose flour
08 - 3/4 cup granulated sugar
09 - 1 teaspoon baking soda
10 - 1/2 teaspoon baking powder
11 - 1/2 teaspoon salt
12 - 1 teaspoon ground cinnamon

→ Mix-ins

13 - 3/4 cup chopped walnuts, lightly toasted

→ Brown Sugar Crust

14 - 1/4 cup packed light brown sugar
15 - 1 tablespoon unsalted butter, melted
16 - 1/2 teaspoon ground cinnamon

# Steps:

01 - Preheat oven to 350°F. Line a 9x5-inch loaf pan with parchment paper or grease thoroughly.
02 - In a large bowl, whisk together mashed bananas, sourdough discard, melted butter, eggs, milk, and vanilla extract until the mixture is smooth.
03 - In a separate bowl, whisk together flour, granulated sugar, baking soda, baking powder, salt, and cinnamon.
04 - Add the dry ingredients to the wet mixture. Stir gently with a spatula until just combined, being careful not to overmix the batter.
05 - Gently fold the toasted walnuts into the batter using a spatula.
06 - Transfer the batter into the prepared loaf pan and smooth the top with a spatula.
07 - In a small bowl, mix the brown sugar, melted butter, and cinnamon. Sprinkle the mixture evenly over the batter surface.
08 - Bake for 50 to 60 minutes, or until a toothpick inserted into the center comes out clean or with only a few moist crumbs.
09 - Cool in the pan for 15 minutes, then transfer the loaf to a wire cooling rack. Allow to cool completely before slicing.

# Expert Advice:

01 -
  • Your sourdough starter finally gets a practical second life, turning what would be discarded into something genuinely delicious.
  • The crumb stays moist for days, and that tangy depth makes it taste more interesting than standard banana bread.
  • Toasted walnuts add a subtle bitterness that plays beautifully against the brown sugar crust, making each slice feel a little special.
02 -
  • The sourdough discard must be unfed and at room temperature; if you use an active, bubbly starter, the bread can rise too fast and collapse in the middle, which I learned the hard way on my first attempt.
  • Don't skip toasting the walnuts, because raw walnuts taste a little bitter in a way that feels off, but toasted ones develop a depth that makes the whole bread taste more intentional.
03 -
  • Always let your sourdough discard come to room temperature before mixing; cold discard doesn't blend smoothly with the other wet ingredients and can create a lumpy texture.
  • If you don't have walnuts on hand, toasting whatever nuts you do have—even five minutes in a dry pan—makes them taste deeper and more interesting in the finished bread.
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