Sourdough Banana Nut Bread (Printable Version)

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

# What You Need:

→ Wet Ingredients

01 - 1 cup mashed ripe bananas (about 2 large bananas)
02 - 1/2 cup sourdough discard, unfed and 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

→ Add-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

# How-To 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 smooth.
03 - In a separate bowl, whisk together flour, granulated sugar, baking soda, baking powder, salt, and cinnamon.
04 - Add dry ingredients to wet mixture. Stir gently with a spatula until just combined; avoid overmixing.
05 - Fold toasted walnuts into the batter.
06 - Pour batter into prepared loaf pan and smooth the top surface.
07 - In a small bowl, mix brown sugar, melted butter, and cinnamon. Sprinkle evenly over batter.
08 - Bake for 50 to 60 minutes, or until a toothpick inserted into the center comes out clean.
09 - Cool in the pan for 15 minutes, then transfer to a wire rack to cool completely before slicing.

# Expert Advice:

01 -
  • You're finally using up that sourdough discard guilt-free instead of pouring it down the sink.
  • The tangy depth from the starter makes this taste more interesting than typical banana bread, without tasting sour.
  • That brown sugar crust on top creates a little crackle when you slice into it that feels like a small celebration.
02 -
  • If your sourdough discard is cold from the fridge, let it sit at room temperature for 30 minutes before mixing—cold discard won't blend smoothly and can create gummy pockets.
  • Don't skip toasting the walnuts; it transforms them from bland to complex and gives you that restaurant-quality depth.
  • A toothpick with a few moist crumbs is actually perfect—pulling it out completely clean sometimes means you've slightly overbaked the edges.
03 -
  • Room-temperature ingredients are non-negotiable here—they mix more thoroughly and create a more tender crumb than cold eggs or milk straight from the fridge.
  • If your brown sugar crust starts to brown too quickly, tent the loaf loosely with foil for the last 15 minutes of baking and remove it to finish crisping.
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