Preheat your oven to 180°C / 350-375°F / Gas Mark 4-5.
Use room temperature butter to grease a 12 cup muffin tin or fill with patty pan liners.
Combined oats, buttermilk, oil and egg in a large mixing bowl. Give it a stir and then let it sit for 10 to 15 minutes. Use this time to mash the bananas. Note 7
Add flour, sugar, baking powder and salt. Use a wooden spoon and stir to combine.
Add blueberries and mashed bananas, stir gently to combine.
Spoon into muffin tin and oven bake for 30 mins in preheated oven. Use a skewer at the 25 min mark to see if they are done. If it comes out clean they are. If is has wet blueberries or banana, test in another part of the muffin, it should have no wet batter.
Use an oven mit to remove the muffin tray from the oven and place on a wire rack. After about 5 mins, remove muffins from tin and allow to cool. Note 8
To serve the muffins, ensure they have been heated, smear with butter, drizzle with honey and dust with icing sugar!