Place all ingredients, chopped white chocolate, heavy cream, butter and vanilla in a bowl. Heat in microwave or double boiler until melted and smooth.
Cover with plastic wrap on contact and chill for 2 hours in the fridge.
Form balls with your hands or a small ice-cream scoop.
Melt the white chocolate in the microwave or double boiler and dip each ball into the melted chocolate to coat. Leave to harden completely on a sheet of baking paper.
Decorate with a little melted dark chocolate and a piping bag and enjoy!