Cut the cling foil into 10 rectangles and set them aside. If you want thicker brownies, only make 8.
Melt the coconut oil and the peanut butter in a sauce pan over very low heat.
Mix in the unsweetened cocoa powder and the mashed bananas. Stir very well and keep mashing the banana until everything is well combined. You should get a smooth mass that no longer sticks to the side of the pan. It takes a few minutes of mashing and stirring but it's well worth it!
Turn off the heat and mix in the cashews. If you use unsalted cashews make sure to add a pinch of salt.
Put a little bit of the mixture on each cling foil bit and wrap it up carefully. Press it into a bar shape.
Put the wrapped up brownies into a freezer-proof container and store them in the freezer. Wait at least 12 hours before you try one. Take it out at least 10 minutes before you are ready for dessert. Enjoy!
Notes
Take the brownies out of the freezer and leave them to thaw for ten minutes before you eat them. Wait less time in summer!