Preheat the oven to 180 degrees Celsius (350 degrees Fahrenheit) on conventional mode.
Melt the butter and let it cool down.
70 g butter
Whisk together the eggs, sugar, and vanilla paste until fluffy.
3 eggs, 2 tsp vanilla paste, 120 g sugar
Add the all-purpose flour, baking powder, salt, and cocoa powder to the batter and mix it together. Then add the melted butter to the batter.
140 g all-purpose flour, 1 ½ tsp baking powder, 1 pinch salt, 35 g cocoa powder
Roughly chop the chocolate and mash the banana with a fork. Fold them into the batter and mix until smooth.
3 bananas, 75 g dark chocolate
Divide the batter into 12 muffin liners, filling them about 2/3 full as they will rise slightly during baking.
Bake the muffins for 20-25 minutes at 180 degrees Celsius (350 degrees Fahrenheit) until the batter is cooked through and does not stick when a toothpick is inserted into the middle of a muffin and pulled out.
Let them cool down before decorating.