Preheat the oven to 180° and line a 23x33cm pan with parchment paper.
Add the butter in a pan and warm it up with the sugar until the butter is melted fully. Let it cool down a little.
225 gr butter, 200 gr sugar
Whisk the eggs with the vanilla until fluffy.
1 tsp vanilla extract, 2 eggs
On a flat plate, mash the bananas, add them to the egg mixture and whisk them together.
3 bananas
Add the butter to the egg mixture as well, stir together well.
Take an other bowl, sift all the dry ingredients in it and stir them together. Mix it well with the wet ingredients together, but don't overmix it.
155 gr flour, 60 gr cocoa powder, 1 tsp baking powder, ½ tsp salt
Stir in the chocolate chips and pour the batter into the prepared pan.
250 gr dark chocolate chip
Optionally place chocolate on the top of the brownie before baking.
Bake for about 20 minutes (180°) until a toothpick comes ot with just a few damp crumbs.