These banana brownies are rich, fudgy, and have a signature crackly crust, with sweet ripe bananas adding natural moisture and cutting through the bitterness of the dark chocolate.
Preheat your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, leaving an overhang on the sides for easy removal later.
In a large mixing bowl, add the butter and the dark chocolate. Melt completely in the microwave or in a bain-marie until smooth and glossy.
Into a large mixing bowl, add the eggs and sugar. Use a whisk to whisk the eggs and sugar for 3 minutes until the mixture becomes pale and thick.
In a separate bowl, mash the ripe bananas thoroughly with a fork or masher until they turn into a completely smooth puree with no chunks remaining.
Transfer the melted chocolate and butter mixture to the egg mixture and sift in the cocoa powder. Add the vanilla extract, banana puree, salt, and espresso powder. Whisk until fully combined and smooth.
Sift the flour into the bowl and fold the mixture with a rubber spatula until the batter is almost combined. Do not overmix!
Pour the batter into your parchment paper-lined 8 by 8 brownie pan and smooth it out with an offset spatula. Bake in a 180°C (350°F) preheated oven for 30–35 minutes. Do not overbake it to keep it fudgy!
Allow the brownies to cool for at least 30 minutes before slicing so they won't crumble and fall apart. Top every slice of brownie with a fresh slice of banana before serving.
Notes
Bananas: Make sure your bananas are heavily spotted or mostly brown. Very ripe bananas are sweeter, softer, and mash into a completely smooth puree, which prevents unwanted gummy pockets in the baked brownies.
Egg & Sugar Whisking: Do not skip whisking the eggs and sugar for the full 3 minutes. This process dissolves the granulated sugar and incorporates air into the eggs, which is the exact secret to getting that thin, shiny, paper-like crackly crust on top.
Chocolate Selection: Use dark chocolate bars with at least 60% cocoa solids. Avoid using milk chocolate or chocolate chips for melting into the butter, as they contain higher sugar levels and stabilizers that can ruin the fudgy texture and make the batter overly sweet.
Cooling Time: Allow the brownies to cool in the pan for at least 30 minutes before lifting them out with the parchment overhang. They need this time to set properly—cutting them too early while hot will cause them to crumble and fall apart.
Fresh Banana Topping: Place the fresh banana slices on top of each brownie square right before serving so they stay bright and appealing. If you need to slice and display them ahead of time, lightly brush the banana slices with a tiny drop of lemon juice to prevent browning.
Measuring Flour: For the best texture, weigh your flour with a digital scale. If measuring by volume, fluff your flour with a spoon, scoop it loosely into your measuring cup, and sweep off the excess with a flat edge. Packing the flour will result in a cakey brownie.