Preheat oven to 180°/350F and line a rectangular baking dish with baking parchment.
Rinse the kidney beans under water and blend them in a food processor along with sunflower oil until smooth. You can also use a hand blender.
Add in all other ingredients apart from the chocolate and mix.
Fill the batter into the prepared baking dish, chop the chocolate and sprinkle over the batter.
Bake on the middle rack for about 20 minutes. Take out the brownies and let them rest for a couple of minutes. Remove from the baking dish and let cool on a wire rack. Cut in pieces and enjoy!
The brownies can be stored in the fridge for several days. They taste delicious when cooled.