Sourdough Discard Banana Cake

A slice of sourdough banana cake on a plate.

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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!

Prep Time20

Cook Time30

Course: Desserts

Cuisine: American

Keyword: soudough banana cake, sourdough discard recipes

Servings: servings

Author: Dahn Boquist

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.

Video

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.

Nutrition