Put thinly peeled orange peel with the sugar in food processor. Add softened butter and process, adding the eggs. Measure the flours and put juices in ½ cup measure, making up the amount with water. Mix and put in ring tin. Bake 180ºC (350ºF) for 40 minutes. Leave stand 5-10 minutes. Dust with icing sugar. Serve warm with strawberries and cream or cold and iced as a cake.