Gently melt the chocolate over a Bain Marie. Once melted stir until completely smooth
Meanwhile put the cream into a small jug and heat until scalding (but not boiling) in the microwave
Use a mini whisk to mix in the custard powder until smooth (ensure no lumps remain)
Pour the milky mixture over the white chocolate, add the vanilla bean paste and mix in
Let cool to room temperature, cover and chill for 3-4 hours
Crumble the shortbread biscuits until they look like breadcrumbs
Divide the mixture into 12-14 portions weighing approx 10g each. Shape into balls and roll in the biscuit crumbs
Store in an airtight container in the fridge for up to 1 week. Bring to room temperature before eating
Notes
I used Birds custard powder - the type that comes in a drum and is blended with milk. I do not recommend using the Instant powder from sachets that is made with boiling water.