Place the all purpose flour in a small bowl and rub in the butter, mix in just enough water to bind ingredients. Press dough into a ball, cover, freeze about 30 minutes or until firm.
Preheat the oven to 200C . Grease a 6 hole (3/4 cup deep) muffin tray.
Heat oil in a frying pan, add onion, cook, stirring, until soft and lightly brown. Set aside to cool.
Sift self raising and extra flour into a large bowl, stir in half the onion, half the cheese and all of the chives, then egg, buttermilk and extra oil.
Spoon the mixture into prepared tray. Grate frozen dough into a small bowl, quickly mix in remaining onion and cheese. Sprinkle over muffins.
Bake muffins for about 25 minutes. Serve warm with chive butter ( I served them with garlic butter, which is my latest craze. Its strange how I have come from a garlic hater to a garlic lover :P)