Preheat oven to 200°C.
Sift the dry ingredients together.
Add half of the grated orange rind to the flour and mix through.
Beat the juice, butter, oil, milk, eggs and vanilla together until mixed.
Add with the bananas to the flour and gently mix through.
Do not over mix, mixture can still be lumpy.
Spoon batter into the hollows of a greased muffin pan.
Top with the remaining orange rind and bake for 20 - 25 minutes or until a skewer comes out clean when inserted.
Allow muffins to cool for 5 minutes in pan before turning out onto a wire rack.
Serve warm or at room temperature with butter.