Heat the heavy cream until just simmering. Pour over the chocolate and wait 1 minute before whisking until smooth. Add the vanilla and then pour into the pie crust. Place in fridge and chill for 3 to 4 hours, until set.
To make the meringue, beat the egg whites at medium speed for 1 minute, until foamy, and then add the sugar. Continue to beat to a stiff peak.
Fold in the marshmallow cream and fold together to combine.
Spread the meringue over the pie. To serve, brulee the meringue with a kitchen torch.