Preheat: Adjust the oven racks so the tray can be placed in the middle of the oven. Preheat the oven to 415°F (210°C). Then line a 12-Muffin pan with muffin liners or coat with butter/oil if you don't have liners.
Prepare 2 mixing bowls: one for dry and another for wet ingredients.
In the first bowl: sift the self-raising flour into the bowl, then add the superfine sugar and oat bran, mix well, make a well in the middle, and set aside.
In a second bowl: Add melted butter, milk, and eggs and whisk together. In a separate bowl, mash the bananas and then add them back to the butter, milk, and egg mixture.
Wet and dry: Pour the wet ingredients into the well of the dry ones and, using a silicone spatula or metal spoon, stir until just combined, but don’t over-mix. (See note number 1)
Filling the tray: Fill each muffin liner with the batter to around 2/3 (approx 3 scoops each). Bake the muffins for approximately 18 minutes or until golden.
Cooling: Allow the muffins to remain in the pan for 5 minutes to cool down slightly before removing them from the tray and onto a cooling rack. Wait for them to cool and enjoy!