Auntie Betty’s Shortbread

1. Place margarine and butter in mixing bowl, add sugar and mix together.
2. Add flour and beat well until light and fluffy.
3. Divide mixture into three 8″/20cm round tins.
4. Spread into tins with a palette knife and prick with a fork.
5. Bake until just beginning to change colour.
6. Switch off oven, cut into triangles and sprinkle with caster sugar.
7. Return shortbread to oven and allow to cool.