This peanut butter banana layer cake is comprised of three layers of banana cake frosted with a simple peanut butter buttercream.
Could banana bread get any better? Yes!
Covert it into a banana cake and frost it with sweet, creamy peanut butter buttercream. While you’re at it, go ahead and sprinkle on some colorful nonpareils for extra credit.
Traditionally, we get each other donuts for our birthdays. Being an overachiever, I also bake him a cake every year. (And I’m happy to do so.)
Banana Cake with Peanut Butter Frosting
As with banana bread, this layer cake is best made with ripe bananas (meaning soft and spotty).
Easy Peanut Butter Buttercream
The peanut butter buttercream used for this cake is a quick variation on the standard American buttercream. Smooth peanut butter is whipped with softened butter and powdered sugar.
The buttercream works best using a no-stir homogenous peanut butter like Jif or Skippy.
If you use a natural peanut butter that requires stirring, the buttercream may separate in the fridge.
This cake rather plain and simple from the outside. It’s the kind of no-frills cake you easily bake during the week!
Cake Storage and Leftovers
Assembled cake can be left at room temperature for up to 24 hours.
Once cake has been sliced, use a small piece of wax paper or parchment paper to cover exposed cake areas. This will prevent cake layers from drying out.
Hold cake in the fridge for longer storage. Let sit at room temperature for 30 minutes or so to allow cake to soften.
Peanut Butter Banana Layer Cake
- ¾ cup unsalted butter, room temp
- 1 cup granulated sugar
- 3 large eggs
- 1 teaspoon pure vanilla extract
- 4 ripe bananas, mashed
- 3 cups all-purpose flour
- 1 teaspoon baking soda
- 1 teaspoon baking powder
- ½ teaspoon kosher salt
- 1 cup milk, whole or 2% reduced fat
- ¼ cup sour cream
Peanut Butter Buttercream:
- 1 cup unsalted butter, room temp
- ½ cup smooth peanut butter*
- 4 cups confectioners’ sugar
- 4-6 Tablespoons milk or cream, depending on desired consistency
- Preheat oven to 350° F. Grease and line three 6-inch round cake pans with parchment paper. Set aside.
- In the bowl of a stand mixer fitted with a paddle attachment, cream butter until smooth. Add sugar and continue to mix until well combined. Scrape down sides of bowl as needed.
- Add eggs one a time and mix until incorporated. Add vanilla and mashed bananas. Mix until combined.
- In a medium bowl, whisk together flour, baking soda, baking powder, and salt. In another bowl, mix together milk and sour cream. (It does not need to be smooth)
- Add 1/3 of dry mixture to mixing bowl and mix on low speed. Follow with half of milk mixture. Repeat and end with remaining 1/3 of dry mixture. Mix until there are no longer any dry streaks of flour in batter.
- Distribute batter evenly among prepared cake pans. Smooth and level batter using a mini offset spatula or spoon. Bake for 30-35 minutes, rotating pan midway through baking. Insert toothpick in center of cake to check for doneness. If toothpick does not come out clean, bake for another 5-8 minutes.
- Let cake cool in pan for 5 minutes. Loosen cake edges from pan using a mini offset spatula. Remove cake from pan and let cool to room temperature on wire rack.
Peanut Butter Buttercream:
- In the bowl of a stand mixer fitted with a paddle attachment (or using an electric hand mixer), cream together butter and peanut butter. Slowly add confectioners’ sugar. Add vanilla and 4 tablespoons of milk. Mix until buttercream is smooth.
- If necessary, level the tops of cooled cakes. Place one cake layer on cake stand or serving platter. Add peanut butter buttercream and smooth into an even layer using an offset spatula.
- Place second cake layer on top. Add another dollop of buttercream and smooth into an even layer. Repeat with remaining cake layer.
- Crumb coat the top and sides of the cake with buttercream. Let chill in the fridge for 10-15 minutes to allow frosting to set. Add a second coat of buttercream on the top and sides of cake. If desired, transfer remaining buttercream to a piping bag fitted with a star tip. Pipe a border along the top of cake. Garnish with sprinkles.
- Buttercream recipe uses a no-stir homogenous peanut butter like Jif or Skippy. If you use a natural peanut butter that requires stirring, the buttercream may separate in the fridge.