Put the Mars bars, milk and cocoa in a heavy-based saucepan. Cook over a very gentle heat, stirring constantly, until the chocolate has melted. Transfer to a bowl and leave to cool for 15 minutes, whisking frequently with a wire whisk to blend in any pieces of fudge that rise to the surface, to leave a smooth mixture.
Whisk the egg whites in a separate bowl until softly peaking. Using a metal spoon, fold a quarter of the whites into the chocolate sauce to lighten it, then fold in the remainder.
Turn the mixture into six small cups, glasses or ramekins and chill in the fridge to set, for at least 2 hours, before serving. Serve topped with chocolate shavings.
Make it differentIn the photograph, they’ve been dressed up for a dinner party, but for a family pud you can set the mixture in one large bowl for everyone to dive into.
Please notePlease note that this recipe contains raw eggs and should be avoided by the very young, the elderly and pregnant women.