• Preheat the oven to 350°F (180°C). Line an 8-inch x 8-inch brownie pan with parchment paper. Set aside.
• In a high-speed blender, add ripe banana pieces, coconut oil, peanut butter, vanilla extract, coconut sugar, unsweetened cocoa powder, salt, baking powder, and rolled oats. If you want to use all-purpose flour, don't add in the blender, or the brownie will be ultra gummy. Set aside in a bowl and blend the remaining ingredients
• Blend on high speed until smooth and well combined with no lumps. You may have to stop the blender a few times, scrape down the side of the jug, and repeat, or use the tamper attachment tool to push ingredients next to the blade.
• If you used all-purpose flour, transfer the batter onto the bowl with flour, stir to combine, and form a thick batter.
• Transfer the brownie batter onto the prepared pan.
• Use a spoon to add dollops of peanut butter on top of the batter.
• Use a skewer to swirl the peanut butter into the brownie batter and create a swirl effect.
• Bake for 20-25 minutes or until the batter is set - if you move the pan the batter won't jiggle or move.
• Let the brownies cool down for 10 minutes in the pan, then pull out the hanging pieces of parchment paper to transfer the brownie onto a cooling rack.
• Cool completely - about 1 hour at room temperature - before cutting into 16 squares.

Storage

• Store brownies in an airtight box in the fridge for up to 5 days or freeze.