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Cut pieces of Brown Butter Banana Cake with Chocolate Fudge Frosting on a marble surface with gold knife and topped with multi-color crispy pearls.

Brown Butter Banana Cake with Chocolate Fudge Frosting

This brown butter banana cake is surprisingly light for a banana cake, with the perfect balance of sweetness and ripe banana flavor that's enhanced by the nutty brown butter, with a deeply chocolate fudge frosting to finish it off.
Yield: one 13x9-inch cake (about 24 servings)
Cook Time: 25 minutes
Total Time: 2 hours

Ingredients

For Banana Cake:

  • ½ cup / 113 g salted butter, ideally European style
  • 2 cups / 250 g all-purpose flour
  • ¾ teaspoon baking powder
  • ¼ teaspoon baking soda
  • ¼ teaspoon fine sea salt, increase to 1/2 teaspoon if using unsalted butter
  • 3 large / 300 g very ripe bananas, mashed (about 1 cup mashed)
  • 1 cup / 200 g granulated sugar
  • 2 large eggs, at room temperature
  • ¾ cup / 190 g full fat buttermilk
  • 2 tablespoons / 28 g vegetable oil
  • 1 tablespoon vanilla extract

For Fudge Frosting:

  • 6 oz / 170 g 60-70% dark chocolate, finely chopped
  • ¼ cup / 50 g granulated sugar
  • 6 tablespoons / 40 g Dutch process cocoa powder, sifted
  • pinch fine sea salt
  • ¾ cup / 180 g heavy cream
  • 2 tablespoons / 42 g glucose syrup, or substitute corn syrup or golden syrup
  • 2 tablespoons / 28 g butter
  • ⅓ cup / 80 g sour cream, at room temperature

Instructions

  • Preheat oven to 350 degrees F. Lightly butter and line a 13-by-9-inch metal baking pan with parchment paper; lightly butter parchment.
  • To brown butter, place butter in a small, heavyweight saucepan (a light colored finish will make it easier to see the color of the butter.) Set over medium heat until butter is fully melted. As it continues to heat, it will get frothy and sputtery. Continue to cook, stirring occasionally, until the solids settle in the bottom of the pan and turn light golden brown. At this point the foaming and sputtering will have subsided as well as most of the water has been cooked off.
  • Remove from heat and transfer to a medium-sized, heat-proof mixing bowl along with sugar, stirring until it forms a smooth, grainy paste, and cools down slightly until it's no longer hot to the touch.
  • Whisk flour, baking soda, baking powder, and salt together in a bowl and set aside.
  • In another bowl or a 2-cup glass measuring cup, mash ripe banana until smooth.
  • Once butter-sugar mixture is lukewarm, whisk in eggs, one at a time, until smooth and incorporated, then whisk in mashed banana.
  • Add half of flour mixture and stir until almost but not quite incorporated, then mix in in half of buttermilk along with vegetable oil and vanilla extract.
  • Fold in remaining flour, and finally stir in the second half of buttermilk, mixing until just incorporated. Pour into prepared baking pan.
  • Bake for about 25 minutes or until a toothpick inserted near the center comes out mostly clean with just a few moist crumbs attached (but no gooey batter). Set on a cooling rack and let cool for 30 minutes, then use the parchment paper to lift the cake out of the pan and onto the cooling rack to cool completely. At this point the cake can be wrapped in plastic wrap and placed in a large plastic bag and frozen for up to 2 months.
  • For fudge frosting, place chopped chocolate in a heat-proof bowl and set aside.
  • whisk sugar, cocoa powder, and salt together in a medium saucepan set over medium heat. Whisk in heavy cream and glucose syrup, and add butter. The mixture will be pretty thick and pasty at first, but will thin out as the butter melts and the sugar dissolves.
  • Cook over medium heat, stirring occasionally, until mixture starts to steam and bubble around the edges. It won't fully boil, but if you tilt the pan, the thin parts will sizzle a bit around the edges.
  • Pour hot cream mixture over the chopped chocolate in the bowl; let sit for 30 seconds, then gently whisk, moving in concentric circles starting from the center out, until chocolate is fully melted and mixture is smooth and shiny. Whisk in sour cream.
  • Let frosting cool at room temperature, stirring every 5 to 10 minutes to ensure it cools evenly, for about 1 hour or until stiff enough to hold soft peaks (it will still be shiny though). You can refrigerate it to cool it quicker, but keep a close eye on it: set a timer so you don't forget to stir it every 5 minutes.
  • Once the frosting is thick enough to hold soft peaks, spread onto cooled cake in loose, rustic swirls. Optionally top with chocolate crisp pearls or other decorations as desired.
  • Cake can be sliced into squares and served immediately, or refrigerated until ready to serve. Leftovers will keep in an airtight container for up to 5 days.