Moist, flavorful, and finished with the best cream cheese frosting, this sourdough banana cake is a great way to use up starter discard. Bakes in under 20 minutes in a jelly roll pan—no loaf pan, no long wait.
Prep Time:15 minutesmins
Cook Time:20 minutesmins
Cooling time:1 hourhr
Total Time:35 minutesmins
Ingredients
For the Cake
2very ripe bananasmashed
½cupgranulated sugar
½cupbrown sugar
½cupvegetable oil
2eggs
1teaspoonvanilla extract
2cupsall-purpose flour
1teaspoonbaking soda
1teaspoonbaking powder
½teaspoonsalt
2teaspoonsground cinnamon
½cupsourdough starterdiscard/ unfed state
For the Frosting
4ouncescream cheeseroom temperature
6tablespoonsbutterroom temperature
1teaspoonvanilla extract
2½cupspowdered sugar
Instructions
The cake
Prep. Preheat oven to 350°F. Grease a 10x15-inch jelly roll pan with baking spray or shortening and dust lightly with flour.
Beat wet ingredients + sugar. In a large bowl, beat together the mashed bananas, granulated sugar, brown sugar, and oil. Add the eggs and vanilla and mix until smooth.
Add ingredients. Add the flour, baking soda, baking powder, salt, and cinnamon directly into the bowl. Mix until just combined. Stir in the sourdough discard by hand.
Bake. Pour the batter into the prepared pan and smooth the top. Bake for 17–20 minutes, or until the top springs back when lightly touched and a toothpick inserted in the center comes out clean. Let cool completely in the pan.
The frosting
Make frosting. Beat the cream cheese and butter until smooth. Add the vanilla and beat to combine. Add the powdered sugar in two batches, mixing on low, then beat briefly on medium until smooth.
Assemble. Spread frosting over the cooled cake and cut into squares to serve.
Notes
This cake also works well in a 9-inch square or round pan—bake for 45–50 minutes.
Don’t like cream cheese frosting? A caramel glaze or dusting of powdered sugar would be great too.
Store covered in the fridge for up to 5 days.