Melt the chocolate. Cream the margarine and sugar until very pale, then add the melted chocolate, essence and milk. Beat in the dry ingredients, beating until the mixture is really light.

Fill the piping bag then pipe quite deep whirls into a circle measuring 20-22.5cm (8-9 inches) on a baking tray. Pipe extra whirls on another tray, allowing room to spread. Bake at Gas Mark 5, 190 °C, 380°F for 15-20 minutes until cooked. Leave to harden before lifting off. Freeze for up to 3 months if required, packing carefully.

Whisk cream and yoghurt together and pipe onto the biscuit base. Decorate with slices of fruit and a few biscuit whirls - eat the remainder !