Cakes Fancy Desserts Layer Cake

Peanut Butter Banana Layer Cake

I don't think I've ever seen an entire cake consumed so quickly and completely. The birthday girl got to take home one final slice, but otherwise this cake disappeared. And it got high praise from kids and adults alike.

Have I mentioned that baking is how I show love? Given that I don’t actually like bananas, this peanut butter banana cake was a true labor of love – which, according to reports, turned out (and I quote) “bangin!”

Admittedly, there were a lot of people at my friend’s birthday dinner last night, but I don’t think I’ve ever seen an entire cake consumed so quickly and completely. The birthday girl got to take home one final slice, but otherwise this cake disappeared. And it got high praise from kids and adults alike.

So even though baking this cake was fraught with a number of minor fiascos, it was well worth the effort. Nothing makes me happier than ensuring a friend has a delicious birthday cake. Because birthday cakes are meant to be delicious, and most store bought cakes give cakes a bad rap, ’cause they’re often dry and the frosting is gross. But I digress…

Intellectually, I understand that most people really like the combo of peanut butter and banana – so I was totally on board when my friend asked for such a cake. But since I’m not a fan of banana, constructing this cake (and essentially scrabbling together my own recipe) was quite the endeavor.

I knew that my Momofuku Milk Bar cookbook had a banana cake recipe, and I trust Christina Tosi’s expertise. So I knew I had a killer cake recipe on hand. But her recipes are also typically super-complicated, so I also knew I wasn’t going to follow the whole thing (which entails like four different types of filling and three days of prep). But the cake layer was handled.

I agonized a bit about filling – whether it should be peanut butter or banana. It was definitely going to have a peanut butter frosting, but I wasn’t sure about ratio of banana flavor to peanut butter since PB can be a really strong flavor. Ultimately, I opted for both in between the layers: a banana pudding frosting filling, with a peanut butter drizzle on top. This way, there’s at least a little peanut butter in every bite.

So. Then I just had to make it happen.


A few things to note:

1. Making this cake requires forethought/planning – somewhat more so than I actually achieved. But first of all, you need “rrrrrrripe” bananas. So you have to either acquire bananas a week or so ahead of time – giving them plenty of time to turn brown – or, you have to have some brown/black bananas in your freezer.

2. Give yourself time to track down ingredients. Specifically, you need banana extract – which, I discovered three hours before party-time, Bi-Lo doesn’t carry. Publix does. But this was an additional pain in the ass that I hadn’t anticipated when trying to put the cake together on the day of. Also – make sure you get instant pudding mix not cook and serve. That was another mistake on my part that relates to the next point.

3. It can’t be assembled last-minute. Since the filling is loose/fluffy, it needs time to set in the fridge. For various reasons, I didn’t have this time, and the top layers almost slid off in the car. Thankfully, the cake carrier saved it from complete disaster, but it wasn’t super-pretty by the time it arrived at the party.

All that being said, it was a major hit, and I’d totally do it over again (with a bit more planning). But, as you can see, it’s rather complicated.

Peanut Butter Banana Cake (adapted from Momofuku Milk Bar and various other places online)

Grade: A

For the cake:

  • 12 tablespoons butter, softened
  • 2 cups sugar
  • 2 eggs
  • 1 cup buttermilk (real, not powdered)
  • 4 tablespoons grapeseed oil
  • 1 teaspoon banana extract
  • 4 (or 450 grams, if you have a scale)”rrrrrripe” bananas – the browner the better
  • 2 2/3 cups flour
  • 1 1/2 teaspoons baking powder
  • 1 teaspoon baking soda
  • 1 teaspoon kosher salt

For the banana filling:

  • 1 (3.9 oz) package instant banana pudding mix
  • 1 cup milk
  • 1/2 (8 oz) tub cool whip topping

For the peanut butter drizzle:

  • 1/3 cup peanut butter
  • 1-2 tablespoons butter

For the peanut butter frosting (I always approximate my frostings/make them to taste):

  • 1/2 cup (1 stick) butter, softened
  • 1 heaping cup of peanut butter (plus a bit more to taste)
  • 1-2 cups powdered sugar
  • 1 teaspoon vanilla
  • 1/3-1/2 cup heavy cream

Before starting, cut out 3 9-inch rounds of parchment paper to line the bottom of your cake pans. Trace the bottom, and then cut inside the lines. You’ll thank yourself for this later – I promise.

Heat the oven to 325° F.

Combine the sugar and butter in the bowl of a stand mixer fitted with the paddle attachment and cream together on medium-high for 2 to 3 minutes. Scrape down the sides of the bowl, add the eggs, and mix on medium-high again for 2-3 minutes. Scrape down the sides of the bowl again.

Combine the buttermilk, oil, and banana extract in a liquid measuring cup. Set the mixer to low speed and slowly stream in the liquids. Increase the speed to medium-high and paddle for 5-6 minutes, until the mixture is practically white, twice the size of your original batter, and completely homogenous. (As Tosi explains) You’re basically forcing too much liquid into an already fatty mixture that doesn’t want to make room for it, so if it doesn’t look right after 6 minutes, keep mixing. When you get it, stop the mixer and scrape down the sides.

On very low speed, add the bananas and mix for 60 seconds to ensure all the bananas are broken apart.

Still on low speed, add the flour, baking powder, baking soda, and salt and mix for 45-60 seconds until your batter comes together and any remnant of dry ingredients have been incorporated. Scrape down the sides of your bowl.

Spray 3 9-inch cake pans with cooking spray, then drop in the parchment rounds. Spread the batter as evenly as possible amongst the pans (roughly 2 1/2 cups per pan). Use a spatula to even out the top. Give each pan a tap on the countertop to even out the layer even more.

Bake for 25-30 minutes. At 25 minutes, gently poke the edge of each cake with your finger: the cake should bounce back slightly and the center should no longer be jiggly. Leave the cake in the oven for an extra 3 to 5 minutes if the cake doesn’t pass these tests. (note: my three layers all went into the same oven at the same time, but they differed in baking time by 2-3 minutes each).

Take the cakes out of the oven and cool on a wire rack. When completely cool – get ready to assemble the cake.

For the banana filling: beat the pudding mix and milk together with an electric mixer for 1-2 minutes. Fold in the cool whip.

For the drizzle: melt peanut butter and butter together in a small saucepan.

To assemble: spread a relatively thin layer of banana filling on the bottom layer of cake (you won’t actually use all the filling in the cake). Then, drizzle the peanut butter over the top. Place second cake layer on top, and repeat. Then throw it in the fridge to set while you make the peanut butter frosting.

For the frosting: beat the confectioners’ sugar (start with 1 cup and add later), peanut butter, butter, vanilla, and salt in the bowl of an electric mixer fitted with a paddle attachment. Mix on medium-low speed until creamy, scraping down the bowl with a rubber spatula as you work. Give it a taste and adjust accordingly. Add the cream and beat on high speed until the mixture is light and smooth.

Then, frost the cake and put it back in the fridge for a while. You really want to give this a solid 2 hours in the fridge before trying to transport it. Take it out 20-30 minutes before serving.

And then, bam! You just made an epic cake.

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