8 egg yolks
180ml Marsala vino
40g caster sugar
1 To make the zabaglione, bring a pan of water to the boil and turn down the heat.
2 Put the egg yolks, Marsala wine and sugar into a round-bottomed bowl.
3 Whisk a little, then put the bowl over the pan of water and carry on whisking until you can form a figure-of-eight with the mixture that will hold for a few moments.
4 Shave the white truffle on top of the foam.