Angel food cake

Method

1. Sift the flour and icing sugar together on to a plate to ensure they are well mixed.
2. Whisk the egg whites and cream of tartar until stiff, then gradually whisk in the caster sugar, a spoonful at a time. Gradually sift in the flour and sugar mixture, folding in between each addition using a large metal spoon. Fold in almond or vanilla essence.
3. Spoon into the ring tin and level the surface, taking care not to press out too much of the air. Place the tin on a baking tray and cook in the centre of a preheated oven at 180°C (350ºF, gas mark 4) for 35-45 minutes, until the cake feels just firm to the touch.
4. Remove the cake from the oven and invert the tin on to a wire rack. Leave the cake to cool completely and then ease out of the tin.
5. To make the frosting, pour 300ml (½ pint) water into a saucepan and add the sugar and cream of tartar. Stir over a low heat until the sugar dissolves. Bring to boil and boil rapidly until the temperature reaches 114°C (230°F) on a sugar thermometer, or until a little of the syrup forms a soft ball when dropped into very cold water.
6. Meanwhile, whisk the egg whites until stiff, preferably using an electric food mixer.
7. As soon as the sugar syrup reaches temperature, plunge the base of the pan into cold water to stop the syrup getting any hotter, then pour slowly on to the egg whites, while continuing to whisk. Keep whisking until the frosting holds a stiff peak.
8. Working quickly, as the surface will set and crust quite quickly, spread the frosting over the cake using a palette knife, swirling the surface to texture it. Decorate the surface if required.