Sourdough banana cake takes your classic banana bread up a notch with a rich, nutty flavor from brown butter and a tangy twist from sourdough discard. Maple cream cheese frosting gives it a cozy, sweet finish.

A partially eaten sourdough banana cake.

Here is Why This Sourdough Discard Recipe Works

Brown butter magic: The nutty, rich flavor of browned butter gives this dessert a whole new level of deliciousness—trust me, you’ll never go back to plain butter.

Sourdough discard to the rescue: Got extra sourdough starter? This recipe puts it to good use, adding a subtle tang that balances the sweetness perfectly.

Banana snack cake + frosting for the win: Ripe bananas make the cake super moist, and the maple cream cheese frosting? Let’s just say you’ll want to eat it by the spoonful.

No mixer needed: This recipe is easy to whip up with just a bowl and a whisk, meaning less cleanup and more cake.

The Ingredients

Dairy: Butter, cream cheese, buttermilk
Produce: Bananas
Pantry: Brown sugar, all-purpose flour, powdered sugar, vanilla, baking soda, baking powder, cinnamon, salt.
Other: Maple syrup, sourdough discard,

Ingredients used to make sourdough discard banana cake.

Ingredients used to make frosting for the discard banana cake.

Variations

Chocolate Chunk Variation: Fold in ¾ cup of dark chocolate chunks to the batter. Frost with peanut butter cream cheese frosting and and slice into bars.

Cinnamon Walnut Variation: Add ½ cup of chopped toasted walnuts and a teaspoon of cinnamon to the mixture.

Blueberry Banana Variation: Gently fold in 1 cup of fresh or frozen blueberries into the batter.

If you love this recipe, try our sourdough banana bread or some of our other sourdough recipes.

browning butter in a skillet. — brown the butter

Stirring sugar and brown butter together. — brown the butter

Tips for Sourdough Success

Use ripe bananas. The riper, the better! Overripe bananas will give the cake a sweeter, more intense banana flavor.
Don’t skip browning the butter. This step helps reduce water content in the butter, which is important because the sourdough discard adds extra moisture to the batter.
Make sure your ingredients are at room temperature for a smooth batter and frosting.
If you want a deeper sourdough flavor, you can let the batter sit overnight in the fridge. This long ferment allows the sourdough discard to develop more flavor.

If you love this recipe, try our sourdough coffee cake.

A slice of sourdough discard banana cake.

Storing Leftover Banana Snack Cake

Fridge: To store leftovers, cover it in an airtight container and keep it in the fridge for 3 to 4 days. Let the cake come to room temperature before serving so the butterfat softens, which helps make it even more tender.

Freezing: If you want to freeze the cake, store it in a freezer-safe container. It will keep well in the freezer for up to 3 months.

Several slices of sourdough banana cake.

Use Up That Sourdough Discard in the Best Possible Way

This sourdough banana snack cake is the best way to use the discard from your sourdough starter. It mixes the rich nuttiness of browned butter with a tangy kick from sourdough, all wrapped up with a maple cream cheese frosting that you’ll probably want to eat straight from the bowl.

It’s also the perfect way to use up those overripe bananas you’ve been pretending not to notice.

A slice of sourdough banana cake on a plate.

Sourdough Discard Banana Cake

This sourdough discard banana cake combines the rich, nutty flavor of brown butter with the tangy twist of sourdough discard. Topped with a maple cream cheese frosting, it’s a moist and flavorful way to use up ripe bananas and extra starter. For a deeper sourdough flavor, you can let the batter ferment overnight in the fridge for an extra boost!

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Prep Time: 20

Cook Time: 30

Servings: servings

Calories: 469kcal

Ingredients

8 tablespoons unsalted butter (113 grams)
⅔ cup light brown sugar packed (142 grams)
2 teaspoons vanilla extract
2 large eggs
1 cup bananas mashed (227 grams)
⅔ cup sourdough discard (150 grams)
3 tablespoons buttermilk (32 grams)
1 cup plus 2 tablespoons all purpose flour (136 grams)
1 teaspoon baking soda
¾ teaspoon baking powder
½ teaspoon salt

Cinnamon Maple Cream Cheese Frosting:

8 ounces cream cheese softened (227 grams)
½ cup unsalted butter softened (113 grams)
2 cups confectioners’ sugar (240 grams)
3 tablespoons maple syrup
½ teaspoon vanilla extract
½ teaspoon ground cinnamon
Pinch of salt

Instructions

Preheat and Prepare the Pan: Preheat the oven to 350°F (175°C). Grease an 8″ square pan with nonstick spray or softened butter. Line the pan with a piece of parchment paper extending up and over two opposite sides to create a sling.

Brown the Butter:

In a medium saucepan, melt the butter over medium heat. Continue cooking, swirling the pan occasionally, until the butter foams, then turns a deep golden brown with a nutty aroma, about 5-7 minutes. Be careful not to burn it.
Remove the pan from heat and transfer the browned butter (along with the browned bits) into a heatproof bowl and let it cool slightly.

Make the Cake Batter:

In a large mixing bowl, combine the cooled browned butter, brown sugar, and vanilla. Beat well for 30 seconds.
Add the eggs one at a time, beating well after each addition.
Mix in the mashed banana, sourdough discard, and buttermilk. Stir until fully combined.
Place a sifter over the bowl and add the flour, baking soda, baking powder, and salt. Sift the dry ingredients into the bowl and use a wide spatula to gently fold the mixture until no streaks of flour remain. Be careful not to overmix.
Pour the batter into the prepared pan and smooth the top.

Bake the Cake:

Bake the cake in the preheated oven for 25 to 30 minutes. The cake is done when a toothpick inserted into the center comes out clean or with only a few moist crumbs attached.
Remove the cake from the oven and let it cool in the pan for about 20 minutes then place it on a wire rack to cool completely.

Make the Frosting:

Using an electric mixer, cream the softened butter with the confectioners’ sugar on medium speed until light and fluffy, about 2 minutes.
Add the softened cream cheese and beat until smooth.
Mix in the maple syrup, vanilla, cinnamon, and a pinch of salt. Beat until light and fluffy.
Wait until the cake is completely cooled before covering it with frosting. I added dollops of maple syrup on the top and swirled it into the buttercream.

Notes

When browning the butter, keep a close eye on it. Once it turns golden and starts to smell nutty, remove it from the heat to avoid burning.
If you prefer a deeper sourdough flavor, you can let the batter rest in the fridge overnight for a long ferment. Just remember to bring the batter back to room temperature before baking.
The riper the bananas, the sweeter and more flavorful the cake will be. Overripe bananas with plenty of brown spots work best.
After adding the flour, gently fold it in until just combined. Overmixing can result in a denser, tougher cake.
Let the butter, cream cheese, and eggs come to room temperature before starting.
Lining the pan with parchment paper makes it easy to lift the cake out after baking.