Preheat oven to 180 degrees celsius (fan-forced).
Line a 12 hole muffin tray with muffin liners.
Place bananas into the Thermomix bowl. Mash for 10 seconds, Speed 8. Pour into a bowl and set aside.
Place the butter into the Thermomix bowl (don't worry about cleaning it) and melt for 1 minute, 100 degrees, Speed 2. Scrape down the sides and melt for a further 30 seconds, 100 degrees, Speed 2 (if needed). Allow to cool slightly.
Add the vanilla extract, honey and milk and mix together for 20 seconds, Speed 4. With the blades spinning, reduce to Speed 3 and add the eggs one at a time through the MC hole.
Add the mashed bananas and mix for a further 20 seconds or until well combined.
Add the self-raising flour, caster sugar, baking powder, bi-carb soda, cinnamon and salt and mix for 5 seconds on Speed 4 (use the spatula to help mix).
Divide mixture evenly between the muffin cases. Sprinkle with raw sugar (optional). Cook for 15 minutes or until they spring back when lightly touched in the middle.
Allow to cool in the tray for 5 minutes before transferring to a wire rack to cool completely.