This icing is used on rich fruit cakes and is best spread over a marzipan base. The icing holds peaks well and, depending on the consistency, can be piped attractively, swirled simply or, if made runnier, dribbled from a spoon or piped from a small bag for writing or making lacy patterns. Strained lemon juice adds flavour but will make the icing hard and brittle, so liquid glycerine is used as well. This makes enough to ice the top and sides of a 23cm (9in) round or 20cm (8in) square deep cake.
Sift 500g (1lb) icing sugar into a bowl. Lightly beat 2 egg whites in a second large bowl, then gradually beat in the sugar, 1tablespoon at a time. Add 2tablespoons strained lemon juice and 2teaspoons liquid glycerine, beating until glossy and fluffy, about 15 minutes. Cover with clingfilm until ready to use.
Prepare a cake top and sides with marzipan (above). Spoon icing round the sides and spread evenly, swirling attractively with a palette knife. Spoon the remaining icing on top, and peak with the tip of the knife, dipping the knife quickly in hot water as necessary. Place decorations in the icing before it sets.