Banana Cake with Brown Butter Frosting and Salted Caramel
Layers of deliciously tender banana cake, creamy brown butter frosting, and salted caramel. Everything you want in a banana cake.
Servings 15 slices
Ingredients
Banana Cake
- 3 large ripe bananas (1 1/4 Cups or 310g), mashed
- 2 1/2 Cups (330g) all purpose flour
- 1 tsp baking powder
- 1 tsp baking soda
- 1 tsp ground cinnamon
- 1/2 tsp salt
- 3/4 Cup (170g) unsalted butter, room temperature
- 3/4 Cup (150g) granulated sugar
- 1/2 Cup (100g) packed brown sugar light or dark
- 2 large eggs, room temperature
- 1 1/2 tsp pure vanilla extract
- 1 1/4 Cups (300ml) full-fat buttermilk*, room temperature DIY recipe in notes
Brown Butter Frosting
- 2 Cups (452g) unsalted butter, divided
- 6 Cups (720g) powdered sugar
- 2 tsp pure vanilla extract
- 6 Tbsp whole milk, room temperature
- 1/4 tsp salt, or to taste
Salted Caramel
- 1 Cup (200g) granulated sugar
- 6 Tbsp (85g) unsalted butter, room temperature
- 1/2 Cup (120ml) heavy whipping cream, room temperature
- 1 1/4 tsp salt
Garnishes
- 6 slices fresh or freeze-dried banana
- 4 Biscoff cookies, ground into crumbs
Instructions
Make the Banana Cake
- Preheat the oven to 350°F (177°C). Prepare three 6-inch or two 8-inch round cake pans by spraying the sides with baking spray and fitting a parchment paper circle to the bottom of each pan.
- In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt. Set aside.
- Mash the bananas. You can either mash them with a fork on your cutting board or place them into the bowl of your stand mixer fitted with the paddle attachment and turn it on low speed. The mixer will mash the bananas for you and there’s no need to clean the bowl or paddle before moving on! Once mashed, set the bananas aside.
- In the bowl of your stand mixer fitted with a paddle attachment, beat the butter, granulated sugar, and brown sugar together on high speed until fluffy, about 2 minutes. Scrape down the bowl and paddle. Add the eggs and vanilla and beat on medium-high speed until combined, then beat in the mashed bananas. The batter will look very curdled at this point but don’t worry – it will all come together in the next step.
- With the mixer on low speed, add the dry ingredients in three additions alternating with the buttermilk and mixing each addition just until incorporated. Do not overmix. The batter will be slightly thick.
- Divide the batter evenly between the prepared cake pans and bake for 30-35 minutes. The cakes are done when a toothpick inserted in the center comes out clean. Let the cakes cool in the pan for five minutes before turning them out onto a wire rack for an additional few hours of cooling.
Make the Brown Butter Frosting
- Set 2 sticks of the unsalted butter aside so that it comes to room temperature by the time you're ready for it. Use the remaining two sticks with the instructions for browning the butter below.
- Brown the Butter: Add 1 Cup (2 sticks) of the unsalted butter into a large frying pan and cook over medium heat until the butter melts, stirring occasionally. Continue cooking for another 1-2 minutes while stirring constantly. The melted butter will start to foam on top, then will turn light brown in color and smell deliciously nutty. Remove from heat at this point and transfer to a glass container. Allow it to re-solidify for about 2 hours at room temperature or place it into the refrigerator for about 30 minutes. It should be completely room temperature and thick (about the consistency of a thick caramel) before continuing on with the buttercream recipe.
- Once the brown butter is room temperature, cream the other 1 Cup (2 sticks) of unsalted butter in the bowl of a stand mixer fitted with the paddle attachment. Mix on medium-high until creamy and light in color, about 5 minutes, scraping down the bowl and paddle as needed.
- Add the cooled brown butter and vanilla and mix on medium speed until uniform. Turn the mixer to low speed and add the powdered sugar a few cups at a time, scraping down the bowl and paddle after mixing in each addition. Add the milk and salt and continue mixing on low speed until smooth.
Make the Salted Caramel
- Have everything pre-measured and ready to go (you’ll be constantly stirring). Place the sugar in a medium saucepan over medium-high heat and stir constantly with a wooden spoon, until it melts into an amber-colored liquid and no sugar clumps remain, 5-6 minutes.
- Reduce the heat to medium. Carefully add the butter (it will bubble up when you do) and use a whisk to combine it with the sugar mixture until the butter is fully melted and incorporated, 2-3 minutes.
- Add the heavy whipping cream in a steady stream while whisking. As soon as the cream is incorporated, let the caramel boil for a full minute before removing it from the heat and stirring in the salt.
- Let the caramel cool to room temperature* before using it in a buttercream recipe or as a cake topping. If you’re using it to drizzle over ice cream or warm baked goods, you only need to cool it slightly (20 minutes or so). It will thicken as it cools.
Assembly
- Once the banana cake layers have cooled completely, level and torte each layer to your desired height. Place the first layer on a turntable and pipe a circle of brown butter frosting (aka a buttercream dam) around the edge. Add a thin layer of salted caramel into the center of the buttercream dam. Fill in the rest of the space with more brown butter frosting and add the next layer on top. Here's a detailed tutorial on this filling method.
- Place the next cake layer on top and repeat the process of piping the buttercream circle and filling in the center with salted caramel and brown butter frosting. Place the final layer on top, upside down so that the bottom of the cake layer is the top of the cake. Crumb coat the cake with brown butter frosting and place it in the refrigerator for at least 20 minutes to let everything set up.
- To create the cake design pictured, frost a smooth layer of brown butter frosting around the cake and press Biscoff cookie crumbs onto the bottom third of the cake. Place it back into the refrigerator for at least 30 minutes to create a cold foundation for the salted caramel drip.
- Meanwhile, microwave the Salted Caramel in 5-10 second increments until it's slightly warmer than room temperature and good drip consistency (this post shows examples of perfect drip consistency with Chocolate Ganache and those same rules apply to Salted Caramel drip consistency). When the cake is nice and chilled and the Salted Caramel is perfect drip consistency, drip the cake. Place it back into the refrigerator for 10 minutes to let the caramel set.
- Fit a piping bag with Wilton Tip 1M and fill it with the remaining brown butter frosting, then pipe swirls on top of the cake spaced about 1/4 inch apart. Add a banana slice in between each swirl, then top with more Biscoff cookie crumbs.
Notes
*DIY Buttermilk recipe: add 1 Tbsp + 1 tsp of white vinegar to a jar and top it with 1 1/4 Cup of whole milk. Stir and let sit for at least 15 minutes before using in the recipe.
Make Ahead Tips:
- The banana cake layers can be made ahead and stored at room temperature, covered tightly in plastic wrap, for up to two days. Alternatively, you can cover with plastic wrap and store in the freezer for up to two months before thawing to room temperature.
- The brown butter for the frosting can be made ahead and stored in the refrigerator for up to two weeks. When you're ready to use it, gently reheat in the microwave in 5-10 second intervals until creamy and room temperature.
- The finished brown butter frosting can be made ahead and stored in an airtight container in the refrigerator for up to two weeks. When you’re ready to use it, bring it back to room temperature and re-whip with your stand mixer on low for one minute to bring it back to frosting consistency.
- The salted caramel can be made ahead and stored in an airtight container in the refrigerator for up to two weeks. When you’re ready to use it, reheat it in the microwave in 10-15 second intervals until it reaches room temperature.