Preheat the oven to 160C/325F/Gas mark 3
Cream together the butter, essence and sugar until light and fluffy. Stir in the sifted flours in 2 batches. Press the mixture together firmly. Turn the dough onto a lightly floured surface, knead for 3 minutes.
Divide the mixture in half. Roll each half on a greased baking tray until 18cm round. Push into shape, pinch edges. Mark 8 wedges on the surface of each round, prick with a fork. Bake for about 1 ¼ hours or until lightly browned. Cool before breaking into wedges.
