Place the milk and white chocolate in a medium saucepan. Whisk over medium-low heat, until the chocolate has melted and the mixture starts to come to a simmer.

In a small bowl, mix together the water and cornflour until smooth. While whisking, drizzle it into the hot chocolate mixture and allow to simmer for 2 minutes or so to thicken the mix.

Once thickened slightly, remove from the heat and stir in the vanilla and salt. Serve immediately while hot with some whipped cream and chocolate shaving on top.