The Best Sourdough Banana Bars with Cream Cheese Frosting
You know those bananas sitting on the counter that everyone suddenly refuses to eat the second they get brown spots? Around here, that usually means one thing: banana bars. And not just any banana bars — these soft, fluffy sourdough banana bars with cream cheese frosting.
This recipe has quickly become one of my favorite ways to use up both overripe bananas and extra sourdough discard. The bars are incredibly moist with the perfect light banana flavor, and the cream cheese frosting takes them completely over the top.
They taste like banana bread and banana cake had the most delicious little baby.
The best part? They’re ridiculously easy to make and always disappear fast.
The perfect use for sourdough discard
If you’re a banana bread lover, prepare to become completely obsessed.
Ingredients:
For the Banana Bars
1 ¾ cups sugar (350g)
¾ cup sour cream (190g)
½ cup unsalted butter, softened (113g)
2 large eggs
1 ½ cups mashed ripe bananas (about 3 large bananas)
Heaping ½ cup sourdough discard (140g)
2 teaspoons vanilla extract
1 ½ cups + 2 tablespoons all-purpose flour (230g)
1 teaspoon baking soda
1 teaspoon salt
For the Cream Cheese Frosting
8 oz cream cheese, softened
½ cup unsalted butter, softened
3 ½–4 cups powdered sugar
1 teaspoon vanilla extract
1–2 tablespoons milk or heavy cream, if needed
Method:
Preheat your oven to 375°F.
Grease or line an 11x16-inch rimmed baking sheet with parchment paper.
In the bowl of a stand mixer, combine:
sugar
sour cream
softened butter
eggs
Mix on low speed for about 1 minute. Don’t worry if there are still tiny bits of butter — it all comes together beautifully once baked.
Mix in:
mashed bananas
sourdough discard
vanilla extract
At this point the batter will look a little runny, and that’s exactly what you want.
In a separate bowl, whisk together:
flour
baking soda
salt
Slowly add the dry ingredients into the wet mixture in batches, mixing until combined.
The batter should be thick but pourable.
Spread the batter evenly into the prepared baking sheet.
Bake for 20–25 minutes, or until lightly golden and a toothpick inserted in the center comes out clean.
Let the bars cool for about 10–15 minutes before frosting.
Cream Cheese Frosting
While the banana bars cool, make the frosting.
In a large bowl, beat together the softened cream cheese and butter until smooth and fluffy.
Add the vanilla extract, then slowly mix in the powdered sugar one cup at a time.
If needed, add a splash of milk or heavy cream until the frosting reaches your desired consistency.
Spread generously over the slightly warm banana bars.
And yes — “generously” is important here.
Tips for the BEST Banana Bars
Use ripe bananas
* the darker the bananas, the sweeter and more flavorful your bars will be.
Don’t overmix: Once the flour is added, mix just until combined to keep the bars soft and tender.
Frost while slightly warm: Not hot. Not fully cooled. Slightly warm is the sweet spot so the frosting spreads beautifully without melting completely.
Add walnuts or pecans for crunch: If you love classic banana bread flavors, sprinkle chopped walnuts or pecans over the frosting.
*Because of the cream cheese frosting, store these banana bars covered in the refrigerator for up to 5 days.
They’re delicious cold, but I personally love letting them sit at room temperature for about 15 minutes before serving.
Can You Freeze Them?
Absolutely.
Freeze the unfrosted banana bars tightly wrapped for up to 3 months. Thaw completely, before serving.
Frequently Asked Questions
Can I use active sourdough starter instead of discard?
Yes you can! Either active starter or discard works perfectly in this recipe.
Can I use frozen bananas?
Definitely. Just thaw and drain any excess liquid before mashing.
Can I make these ahead of time?
These bars are actually even better the next day after the flavors have had time to settle together.