Ingredients:

  • 1/2 cup (115 g) Unsalted Butter, cut into cubes
  • 1/4 cup (60 ml) Vegetable Oil (or neutral oil)
  • 1 cup (200 g) Granulated Sugar
  • 1/2 cup (100 g) Light Brown Sugar, packed
  • 1/2 cup (60 g) Unsweetened Cocoa Powder
  • 2 Large Eggs, at room temperature
  • 1 teaspoon (5 ml) Vanilla Extract
  • 2 medium Very Ripe Bananas, mashed (Approx. 200 g / 7 oz)
  • 3/4 cup + 2 tbsp (100 g) All-Purpose Flour
  • 1/2 teaspoon (2 g) Fine Sea Salt
  • Optional: 1/2 cup (85 g) Chocolate Chips
  • 1/2 cup (115 g) Unsalted Butter, softened (for frosting)
  • 1/3 cup (100 g) Smooth Peanut Butter
  • 2 1/2 cups (300 g) Icing Sugar (Confectioners' Sugar), sifted
  • 1 small Ripe Banana, mashed (Approx. 80 g / 3 oz)
  • 1–2 tablespoons (15–30 ml) Milk or Cream (optional)

Instructions:

  1. Preheat oven to 175°C (350°F). Line the 8x8 inch pan with parchment paper, allowing an overhang on two sides (the 'sling').
  2. Melt and Mix Fats: In a medium saucepan, gently melt the cubed butter. Once melted, remove from heat and whisk in the vegetable oil.
  3. Bloom the Cocoa: Add both sugars (granulated and brown) and the cocoa powder to the warm butter/oil mixture. Whisk vigorously for about 30 seconds until a thick, gritty paste forms.
  4. Incorporate Wet Ingredients: Whisk in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract and the mashed ripe bananas until just combined. Do not overmix at this stage.
  5. Add Dry Ingredients: Gently fold in the all-purpose flour and salt using a rubber spatula until just no streaks of flour remain. If using chocolate chips, fold them in now.
  6. Bake: Pour the batter into the prepared pan. Bake for 30–35 minutes.
  7. Test for Doneness: The edges should look set, but the center should still look slightly soft. A toothpick inserted 1 inch from the edge should come out with moist, sticky crumbs clinging to it (not clean).
  8. Cool Completely: Remove from the oven and allow to cool in the pan on a wire rack for at least 60 minutes. Once cooled, lift the brownies out using the parchment sling and transfer to the refrigerator for at least another hour to firm up completely. This chilling step is non-negotiable for a clean cut!
  9. Cream the Fats: In a large bowl or stand mixer, beat the softened butter and peanut butter together until light and fluffy (about 3 minutes). Scrape down the sides.
  10. Add Sugar Gradually: Slowly add the sifted icing sugar, alternating with the mashed banana. Beat on low speed initially to prevent the sugar plume, then increase speed to medium.
  11. Check Consistency: Beat for 3-5 minutes until the frosting is thick, creamy, and pale. If it seems too stiff, add 1–2 tablespoons of milk or cream until it reaches a spreadable consistency.
  12. Frost and Set: Once the brownies are fully chilled and firm, spread the frosting evenly over the top. Return the brownies to the refrigerator for another 30 minutes to allow the frosting to set before slicing.