Soak the gelatin in cold water.
Chop the truffle , split the vanilla pod and scrape the inside.
In a saucepan, bring the milk to a boil with truffle chopped and vanilla.
Add the drained gelatin, then the white chocolate and sugar.
Mix well, until the chocolate is melted then let cool.
When the mixture is cold, add the liquid cream, mix and pour immediately into ramekins. Leave to set in the refrigerator.
Before serving, grate the remaining truffle on the panna cotta.