Sour Cream Banana Cake with Cream Cheese Frosting
A tender, moist sheet cake made with mashed bananas and tangy sour cream, topped with rich cream cheese frosting. The cake has a soft crumb and subtle banana flavor balanced by the sour cream's slight acidity. Perfect for potlucks, celebrations, or casual gatherings. This version uses a simple creaming method and yields an oversized single-layer cake that feeds a crowd, with frosting that spreads easily while still tasting homemade.
Ingredients
- ½ cup butter, at room temperature
- 1 ½ cups sugar, granulated
- 2 eggs, large
- 1 cup sour cream, full-fat
- 1 teaspoon vanilla extract, pure
- 2 cups all-purpose flour, spooned and leveledgluten-free blend1:1celiac-friendlygluten-free
medium
- 1 teaspoon baking soda
- ¼ teaspoon salt, fine
- 2 bananas, ripe, mashed to 1 cup
- 8 ounces cream cheese, at room temperature
- 2 teaspoons vanilla extract, pure
- 3 ¾ cups powdered sugar, sifted
Instructions
- 1
Preheat oven to 350F.
- 2
Spray a 15 by 10-inch jelly roll pan with non-stick spray.
- 3
Cream butter and sugar until light and fluffy using a hand mixer.
- 4
Add eggs, sour cream, and vanilla to the butter mixture and beat well.
- 5
In a separate bowl, whisk together flour, baking soda, and salt.
- 6
Slowly stir the flour mixture into the wet ingredients until combined.
- 7
Fold in mashed bananas.
- 8
Spread batter into the prepared pan.
- 9
Bake for 20-25 minutes until a toothpick inserted in the center comes out clean.
- 10
Cool completely in the pan.
- 11
For frosting, beat cream cheese, butter, and vanilla until fluffy.
- 12
Gradually add powdered sugar until spreadable consistency is reached.
- 13
Spread frosting over cooled cake with an offset spatula.
Tips
Ensure all ingredients, especially butter, eggs, and cream cheese, are at room temperature for smooth mixing and proper emulsification.
Do not overbake; the cake continues cooking as it cools. Check at 20 minutes for doneness to keep the crumb moist.
Measure mashed bananas in a separate cup to ensure exactly 1 cup. Overripe bananas yield more liquid, which may affect texture.
Good to Know
Cover and refrigerate up to 5 days. Frosting protects the cake from drying.
Bake cake 1 day ahead and cool completely, then wrap tightly. Frost on the day of serving for best texture.
Serve at room temperature or chilled. Cut into squares. Pairs well with coffee, milk, or fresh berries.
Common Mistakes
Do not skip cooling the cake completely to avoid the frosting melting or sliding off.
Avoid adding powdered sugar too quickly when making frosting; add gradually to reach spreadable consistency and prevent over-sweetness.
Do not overbake; check at 20 minutes to keep the cake moist and tender.
Substitutions
Dairy-Free Swaps
Gluten-Free Swaps
medium
General Alternatives
FAQ
Can I freeze this cake?
Yes. Wrap unfrosted cake layers tightly in plastic wrap and freeze for up to 2 months. Thaw at room temperature. Frosted cake freezes 3-4 weeks; thaw in the refrigerator before serving to avoid condensation.
What if I don't have a 15 by 10-inch pan?
Divide batter between two 9-inch round pans; reduce bake time to 18-20 minutes. Alternatively, use one 9 by 13-inch pan and bake 25-30 minutes. Adjust frosting quantity accordingly.
How long will the frosting stay spreadable?
Once spread, the frosting sets in about 1-2 hours at room temperature. Keep the finished cake refrigerated for easier slicing and to prevent frosting from softening excessively.