30-Min Fluffy & Moist Banana Oat Flour Cake

Oat flour cake is loaded with banana flavor and has the most fluffy peanut butter frosting on top! This cake is a mix between banana bread meets moist cake.

It’s truly a no-fuss cake. You mix it up in one bowl, bake it up and whip up the peanut butter frosting once it’s cool. Easy peasy.

I made this into a two layer 6 inch cake, but you cake definitely pour the batter into a square or rectangular pan for a sheet pan cake. It may make the slice cutting that much easier, but it’s up to you!

Ingredients and substitutions for this banana oat flour cake:

Bananas. You know those ripe, spotty bananas sitting on your counter? They’re soft, slightly brown? Grab ’em!

Eggs. Just two. If you don’t have any eggs or don’t want to use eggs, you can use your favorite egg replacer.

Agave Nectar. Honey or maple syrup also works if you want to sub it in.

Vanilla Extract. Just a splash for that vanilla, cakey vibes.

Oat Flour. I love using oat flour lately. If you don’t have any oat flour on hand, pulse some old fashioned oats in your blender or food processor until it forms a powder-y flour. Viola! You have oat flour.

Baking Powder & Salt. This is where the baking magic happens.

Ingredients for fluffy whipped peanut butter frosting

Heavy cream. I haven’t tested this with coconut cream or a dairy free alternative, so if you do any experimenting, let me know how it goes!

Peanut Butter. I use natural peanut butter, but other peanut butters or nut/seed butters would probably work here too.

Agave Nectar. For some sweetness! You can sub honey or maple syrup if you prefer!

Make this oat flour cake your own!

I wanted to make a classic banana cake so didn’t fold in any add-ins. But, add 1/2 cup chocolate chips or walnuts (or both!) to add some texture to this cake!

How to make this banana oat flour cake:

Mix up the cake batter. Mash the bananas in a large bowl. Add the eggs, agave nectar, and vanilla. Whisk until combined. Add the oat flour, baking powder, and salt. Whisk again until combined. 

Transfer to a pan and bake. Line an 8×8 or 9×9 square pan with parchment paper and transfer the better to the pan. Bake for 15 minutes until a toothpick comes out clean. 

Cool completely. Allow the cake to cool at room temperature.

Make the frosting. Place the heavy cream in a large bowl. Use an electric mixer and whip on high for 3 minutes until it starts to have soft peaks. Add the peanut butter and agave. Mix again and continue to whip for a couple more minutes until the frosting stiffens and turns into a whipped cream. 

Assemble the cake. Smooth the whipped frosting on top of the cake until it covers the top. Sprinkle with chopped walnuts or whatever fun toppings you’re using!

Chill and enjoy! Enjoy immediately or chill the cake for about an hour for the frosting to firm up a bit.

More banana recipes to try

• Oat Flour Banana Bread
• Chocolate Chip Tahini Banana Bread
• Gluten Free Chocolate Chunk Banana Cake
• Banana Chocolate Chip Bars
• Banana Oatmeal Breakfast Cookies