In France, this light and frothy mousseline sauce is known as sabayon and is spooned over fruity puddings. When freshly made and warm it is delicious served with a light sponge pudding. In Italy, when flavoured with sweet rich Marsala and extra sugar it becomes the classic pudding zabaglione.
For a sauce, allow 1tablespooncaster sugar to each egg yolk. For zabaglione, allow 25g (1oz) sugar and 1tablespoon of Marsala per yolk. The method of making is almost the same.
To make sabayon sauce, put 4 egg yolks and 4 tablespoons caster sugar in a heatproof bowl and beat until frothy, ideally using an electric mixer. If making zabaglione whisk in the Marsala at this stage. Scrape down the sides of the bowl with a rubber spatula.
Slowly bring to the boil, stirring constantly until thickened. It will look alarmingly lumpy at first but keep stirring and the sauce will become smooth. Cook for 1 minute.
Remove the saucepan from the heat. Leave to cool, stirring occasionally to prevent a skin from forming. For a touch of luxury, beat in 2tablespoonsbrandy, rum or sherry.