Banana Bread Bars with Fudge Buttercream

I honestly woke up this morning craving these particular bars, even though I had never made them. I set off to my kitchen and must admit they are the best thing I have made in quite awhile; the moist banana base and rich chocolate buttercream paired perfectly together.

This is a combination of two recipes from my book 100 Afternoon Sweets. The banana bread bars are streamlined here so they are a one-bowl bake. I cut the fudge buttercream in half in the recipe below, but for a thick swoop of frosting (as seen in these photos) you can double the buttercream recipe below and almost use all of it. This banana bread is rich and moist, full of plenty of banana flavor.

It is different than my tried and true banana bread, but I think it is just as good, and easier to make. The fudge buttercream on top is chocolate-y and dense, and pairs perfectly with the banana flavor. It is a decadent treat, but dang, it’s delicious.

The recipe for the banana bread bars also makes a stellar banana bread: just bake in an loaf pan for 50 to 60 minutes, until a toothpick comes out clean. It doesn’t require a stand mixer, it doubles well, and freezes beautifully.

Banana Bread Bars with Fudge Buttercream

Servings: 12 servings

Prep Time: 15 minutes minutes

Cook Time: 30 minutes minutes

Cooling Time: 20 minutes minutes

A moist banana base is topped with rich, fudgy buttercream to make these easy bars. They have great banana flavor, that pairs perfectly with the chocolate.

Sarah Kieffer

No ratings yet

Print Pin Rate

Ingredients

Banana Bread Bars

• 4 tablespoons [57 g] unsalted butter, melted
• 1/2 cup [100 g] granulated sugar
• 1/2 cup [100 g] brown sugar
• 1/3 cup [80 g] buttermilk, at room temperature
• 1/4 cup [60 g] vegetable oil
• 2 large eggs, at room temperature
• 1 tablespoon pure vanilla extract
• 1 teaspoon fine salt
• 1 teaspoon baking soda
• 1 1/2 cups [213 g] all-purpose flour
• 1 cup [227 g] mashed, very ripe bananas (about 3 bananas)

Fudge Buttercream

• 1/2 cup [1 stick or 113 g] unsalted butter, at room temperature
• 1/3 cup [33 g] Dutch-process cocoa powder
• 1 tablespoon corn syrup
• 1 teaspoon pure vanilla extract
• Pinch salt
• 1/4 cup [60 g] cream fraiche (or sour cream), at room temperature
• 1 1/2 cups [180 g] confectioners' sugar

Instructions

For the banana bread bars

• Position an oven rack to the middle of the oven and preheat the oven to 350F [180C]. Grease an 8 in [20 cm] square baking pan and line with a parchment sling.
• In a large bowl, whisk together the melted butter, granulated and brown sugars, buttermilk, vegetable oil, eggs, vanilla, salt, and baking soda. Add the flour and use a spatula to combine it into the batter. Switch to a whisk and whisk the batter to eliminate any remaining flour lumps, about 10 seconds. Add the bananas and stir them in until incorporated.
• Pour the batter into the prepared pan and use the back of a spoon or an offset spatula to smooth the top.
• Bake, rotating the pan halfway through, until the top of the cake is golden and a wooden skewer or toothpick inserted into the center comes out clean, 30 to 35 minutes.
• Let the cake cool for 20 minutes in the pan, then use the parchment sling to remove the cake and let it finish cooling before icing.

For the fudge buttercream

• In the bowl of a stand mixer fitted with a paddle, beat the butter on medium speed until creamy, about 1 minute. Add the cocoa powder, corn syrup, vanilla, and salt and mix again on until light and creamy, 2 to 3 minutes.
• Scrape down the sides of the bowl, add the creme fraiche, and mix on low speed until combined. Add the confectioners' sugar and mix until combined and smooth. The more you mix, the lighter the frosting will get. Finish mixing with a spatula, making sure all the ingredients are evenly incorporated.
• Cover the cooled bars evenly with the buttercream. Slice and serve.

Notes

*If your powdered sugar is lumpy, sifting it before adding it can be beneficial here; the lumps are a little harder to beat out in this buttercream.

*The buttercream can be easily doubled for a thick, substantial frosting layer. 

*These bars also make a great banana bread! Bake in a 8 by 4 in loaf pan for 50 to 60 minutes. 

**Throughout my recipes posted on this website, 1 cup of flour equals 142g. Please note that 1 cup of flour can range anywhere from 120g to 142g, depending on the baker or website. I found that after weighting many cups of flour and averaging the total, mine always ended up around this number. Weighing your flour instead of using cup measurements is the surest way to get the result I intended when developing the recipe.