Banana Cake with Browned Butter Rum Frosting

This moist banana cake is easy to make, with soft and sweet layers studded with crunchy walnuts and swirled with salted caramel! I’ve filled and frosted this cake with fluffy browned butter frosting spiced with a splash of rum.

Banana Cake with Browned Butter Frosting

This homemade banana cake has moist, fruity cake layers filled with crunchy walnuts and salted caramel, covered in fluffy brown butter frosting spiced with a touch of rum. The nutty richness of the frosting pairs SO WELL with the sweetness of the bananas and caramel. If you’ve never made brown butter before, it’s going to knock your socks off! I’ve paired this frosting with everything from zucchini cake to butterscotch cake, and each time, I’m reminded just how special it is.

Why You’ll Love This Banana Cake Recipe

• Soft, banana-filled layers. The banana cake layers are so good, I could eat them on their own! They’re soft and dense, a bit like my favorite banana bread, with bananas and sour cream to help keep the crumb super moist. I baked the cakes in two 8-inch round pans, but you can certainly use 9-inch pans as well.
• All occasions. This decadent banana cake recipe is great for just about any occasion: baby showers, Easter brunch, Mother’s Day, you name it. It would also make the perfect birthday cake for the banana lover in your life.
• Browned butter frosting. Once you’ve browned butter, you’ll be hooked. This stuff is incredible! Brown butter is just as delicious in the frosting for this banana cake as it is in recipes for blondies and chocolate chip cookies. It’s a simple technique that brings rich, nutty flavor to all sorts of desserts.

Ingredient Notes

This recipe needs only some baking staples (flour, sugar, leavening), plus a handful of key ingredients to create a moist cake bursting with banana flavor. These are some quick notes. You’ll find a complete list of ingredients with amounts in the printable recipe card below the post.

• Butter – Salted or unsalted butter, softened to room temperature.
• Bananas – You’ll need about 3 medium-sized bananas. The more ripe they are, the better! The best bananas for baking have brown spots on the peels. Mash them up before you start.
• Sour Cream – The “secret” ingredient in most of my homemade cake recipes. Sour cream makes the crumb extra moist. If you don’t have it, you can also use Greek yogurt.
• Walnuts – Nuts are optional, but I love the texture they add to this banana cake. You can use raw or toasted walnuts or pecans. To toast the nuts, bake them in a 350ºF oven in a single layer for 5-10 minutes.
• Frosting – I use my homemade brown butter frosting. This time, I’ve amped up the recipe with spiced rum and cinnamon to really bring out the flavors in this cake. Use any dark rum you’d like. Brandy or whiskey would also work well. Or, you can skip the alcohol altogether and use milk instead.
• Salted Caramel – Like the frosting, the salted caramel sauce is homemade, too! Feel free to save time with a jar of your favorite store-bought caramel sauce.

How to Make a Banana Cake

The batter for this banana cake is denser than your traditional cake batter, so when you spread the batter in the pans, don’t be alarmed if it looks like you won’t have enough! Trust me, it will bake up to be a nice thick layer of cake. The steps for this banana cake recipe are very easy. Check out an overview here, and scroll to the recipe card for printable instructions.

• Make the batter. First, prepare your banana cake batter, beginning with the wet ingredients. Slowly add the flour and fold in the walnuts. Pour the batter into two greased and lined 8-inch cake pans.
• Bake. Bake the cakes at 350ºF for 20-25 minutes, or until a toothpick stuck into the center of the cake comes out clean. Let the cake layers cool completely while you make your frosting.

Easy Browned Butter Frosting

The frosting for this cake is so easy! It helps to prepare the brown butter ahead of time (see below). Otherwise, you’ll need to budget an extra 30 minutes or so for the butter to cool before making the frosting.

• Brown the butter. The trick to browning butter is to heat it in a pan and swirl it often as it boils. After a while, it’ll give off a nutty aroma and turn deep amber in color as the milk solids start to toast. I have an in-depth tutorial on how to brown butter with tips and a video that walks you through it. It’s really a simple process! Afterward, once it’s cooled, give it a good stir.
• Make the frosting. Now, slowly beat powdered sugar with the browned butter, alternating with rum, milk, and vanilla until that’s whipped and fluffy. Voila! Your browned butter frosting is ready to use.

How to Decorate This Banana Cake

I went for a more rustic look when stacking and frosting my banana cake. Since there are only two layers, I didn’t even level (torte) the cakes like I normally would when making a layer cake. Here’s how to easily assemble and frost the cake:

• Start with the first cake layer. Spread about 1/3 of the frosting over the first cooled cake layer. Give that a swirl with caramel sauce and a sprinkle of nuts.
• Add the second layer. Place the next cake layer carefully over the first. I like to invert the second layer, so that the curved “dome” faces downwards, and the bottom creates a smooth, flat top for the cake.
• Frost the cake. Spread the remaining frosting all over the top and sides of the cake. Garnish with extra nuts and caramel, and enjoy!

How to Store

• Storing. This banana cake is fine to store airtight at room temperature for 2-3 days if your kitchen is fairly cool. Any longer than that, and I’d recommend moving the cake to the fridge. Take the cake out and let it come back to room temperature for serving.
• Freezing. I’d suggest freezing the banana cake layers before you frost them. Wrap them tightly in a double layer of plastic wrap and freeze for up to 2 months. Defrost the cakes completely before assembling and frosting.

More Banana Recipes

• Banana Pudding Cupcakes
• Easy Banana Pudding Poke Cake
• Magnolia Bakery Banana Pudding
• Banana Cream Pie
• Banana Nut Muffins

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