Soft and fluffy Banana Crumb Cake of my dreams! This cake is an easy banana cake with a delicious cinnamon sugar streusel sprinkled on top. It's a great way to use up ripening bananas!

Oh my goodness this cake is so good! The flavours of butter mixed with sweet bananas and cinnamon makes this cake so warming and cozy.
This is a great sweet treat to make ahead of time! It also acts as a delicious breakfast or on-the-go snack.
If you have ripening bananas on your counter and don't want to make your classic banana bread, you have to try this cake!
For more banana recipes, try Banana Oatmeal Muffins, Banana Sour Cream Coffee Cake, and Banana Oatmeal Cookies.
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Why this recipe works
- Bananas - A great way to use up ripening bananas.
- Easy to make - All of the ingredients are simple and no electric mixer required!
- Delicious - This cake is so dang good!

Ingredients Notes
Full recipe and ingredients are in the recipe card below. Feel free to scroll through this section to view certain key ingredients we’re using!
All-purpose flour – This flour is used for the cake and cannot be substituted for any other.
Bananas – 2 large bananas are used. If using frozen bananas, thaw and drain any excess liquid before adding into the bowl.
Brown sugar – I used dark brown sugar, but light brown sugar works as well!
Butter - This will be softened.
Cornstarch – Used to enhance the texture.
Cinnamon - Adds some depth to the flavour!
Eggs – Must be at room temperature before starting your bake.
Sour Cream – The secret ingredient that makes this cake so soft and moist!

Step by step instructions
Here is how to make and bake this banana crumb cake. You will need a 9×9 baking pan lined with parchment paper, 3 mixing bowls, a spatula, and an electric handheld mixer.
Step 1 – Prep. Grease the pan. For easy removal of the cake, place parchment paper on the bottom and 2 sides of the pan. Gently grease the other two sides and then set aside. Mash the bananas.
Step 2 – Make the streusel. In a medium sized bowl, add flour, brown sugar, white sugar, cinnamon, and softened butter. Using a fork or your hands, mix this until combined. Then add 1 tbsp of extra flour on top and using your hands, crumble the streusel into smaller and larger pieces. You may need 1 more tbsp of flour depending on how soft your butter is. Set aside in the fridge when done.

Step 3 – Mix dry ingredients. In another medium sized bowl, add in flour, cinnamon, cornstarch, baking soda, and salt. Stir to combine and set aside.
Step 4 – Cream the butter and sugar. In a large bowl, add softened butter, brown sugar, and white sugar. Beat on medium speed for 2-3 minutes until it’s light and fluffy. Make sure to scrap the sides of the bowl.


Step 5 - Add in the eggs and vanilla. Add the eggs and vanilla into the bowl and mix on medium speed until well combined. Make sure to scrap the sides of the bowl.
Step 6 - Add in bananas. Add in the mashed bananas and mix on medium speed until well combined, scraping the sides of the bowls when needed.
Step 7 - Add the dry ingredients and the sour cream. Slowly add the dry ingredients in three additions, starting and ending with the dry ingredients. Alternate between adding in the dry ingredients and the sour cream. Mix until just combined between each addition.



Step 8 - Scoop the batter. Add the batter into the prepared pan and spread evenly. Sprinkle the streusel on top of the batter.


Step 9 - Bake. Bake the cake for 45-60 minutes. The cake will be ready when a toothpick inserted comes out dry. Mine took 55 minutes.
Remove from the oven and allow to cool before slicing. When ready, slice and enjoy! This banana crumble cake stays good on the counter in an airtight container for 2 days, and in the fridge for up to a week.

Expert Baking Tips
Here are a few expert baking tips from my kitchen to yours
- Make sure all of your wet ingredients are at room temperature. It’s important or else the ingredients won’t work the way we want them too together.
- The type of sour cream you use matters. Make sure it is full fat.
- For the streusel: Make sure the butter is softened. If you make it with melted butter, the streusel will not turn out.
- The riper the bananas the better. They should have lots of black spots on them!

FAQ
Why is there sour cream in this cake and can I taste it?
You cannot taste it at all. Using sour cream in cakes creates a superrrr soft and tender cake. It is what fluffy dreams are made of. If you don’t have any sour cream on hand, use full fat plain yogurt instead.
How far in advance can I make this cake?
This banana crumb cake stays good on your counter for a few days, and in the fridge in an airtight container for a week.
You can also store this cake in the freezer and thaw when ready to eat it! Store in an airtight container for up to a month.

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Banana Crumb Cake
Ingredients
For the cake
- 2 cups all-purpose flour
- 1 tsp baking soda
- 1 tsp cinnamon
- 1 tbsp cornstarch
- 1/4 tsp salt
- 1/2 cup unsalted butter softened
- 1/2 cup dark brown sugar
- 1/2 cup white sugar
- 2 eggs
- 1 tbsp vanilla
- 1 1/4 cups bananas about 3 medium or 2 large
- 1/2 cup full-fat sour cream room temperature
For the streusel
- 3/4 cups all-purpose flour + 2 tbsp
- 1/4 cup white sugar
- 2 tbsp dark brown sugar
- 5 tbsp butter softened
- 1/2 tsp cinnamon
Instructions
- Preheat the oven to 350℉/176℃. For easy removal of the cake, place parchment paper on the bottom and 2 sides of the pan. Gently grease the other two sides and then set aside.
For the streusel
- In a medium sized bowl, add flour, brown sugar, white sugar, cinnamon, and softened butter. Using a fork or your hands, mix this until combined. Then add 1 tbsp of extra flour on top and using your hands, crumble the streusel into smaller and larger pieces. You may need 1 more tbsp of flour depending on how soft your butter is. Set aside in the fridge when done.3/4 cups all-purpose flour + 2 tbsp, 1/4 cup white sugar, 2 tbsp dark brown sugar, 1/2 tsp cinnamon, 5 tbsp butter
For the cake
- In a medium sized bowl, add in flour, cinnamon, cornstarch, baking soda, and salt. Stir to combine and set aside.2 cups all-purpose flour, 1 tsp baking soda, 1 tsp cinnamon, 1 tbsp cornstarch, 1/4 tsp salt
- In a large bowl, add softened butter, brown sugar, and white sugar. Beat on medium speed for 2-3 minutes until it’s light and fluffy. Make sure to scrap the sides of the bowl.1/2 cup unsalted butter, 1/2 cup dark brown sugar, 1/2 cup white sugar
- Add the eggs and vanilla into the bowl and mix on medium speed until well combined. Make sure to scrap the sides of the bowl.2 eggs, 1 tbsp vanilla
- Add in the mashed bananas and mix on medium speed until well combined, scraping the sides of the bowls when needed.1 1/4 cups bananas
- Slowly add the dry ingredients in three additions, starting and ending with the dry ingredients. Alternate between adding in the dry ingredients and the sour cream. I used an electric mixer to add in the ingredients until the last bit of flour, I mixed that in with a spatula. Mix until just combined between each addition.1/2 cup full-fat sour cream
- Add the batter into the prepared pan and spread evenly. Sprinkle the streusel on top of the batter.
- Bake the cake for 45-60 minutes. The cake will be ready when a toothpick inserted comes out dry. Mine took 55 minutes.
- Remove from the oven and allow to cool before slicing. When ready, slice and enjoy! This banana crumble cake stays good on the counter in an airtight container for 2 days, and in the fridge for up to a week.
Mabeline G. says
I followed your recipe except I used light brown sugar because I didn't have the dark one. Cake turned out great!! Had no problems. Will bake again. Thank you.
Ania says
Hi Mabeline! Thanks for your sweet comment! I'm really happy to hear the recipe turned out delicious for you and that you'll keep it in your baking rotation 🙂 Have a wonderful day!