Place bananas and vanilla bean paste into the Thermomix bowl and blend 8-10 sec/speed 10. This will be very loud.
Scrape down sides of bowl and add cream and maple syrup. Blend 5 sec/speed 6. Scrape down sides of bowl and insert Butterfly.
Whip 10 sec/Butterfly/speed 4. Add cacao nibs or chocolate through hole in lid and whip further 5 sec/speed 4.
Serve immediately. This will freeze very hard. You can bring it back to soft serve by putting it into the fridge to 'warm up' for 10 minutes or so. Alternatively you can re-blend but you will lose the crunchiness of the cacao nibs.