Makes enough to cover one 20 cm / 8 in cake
450g/1 lb/2 cups caster (superfine) or
150 ml water
15 ml/1 tbsp liquid glucose or
2.5 ml cream of tartar
Dissolve the sugar in the water in a
large, heavy-based pan over a low heat. Wipe down the sides of the pan
with a brush dipped in cold water to prevent crystals forming.
Dissolve the cream of tartar in a little water, then stir into the
pan. Bring to the boil and boil steadily to 115°C/242°F when a drop of
icing forms a soft ball when dropped into cold water. Slowly pour the
syrup into a heatproof bowl and leave until a skin forms. Beat the
icing with a wooden spoon until it becomes opaque and firm. Knead
until smooth. Warm in a heatproof bowl over a pan of hot water to
soften, if necessary, before use.