Melt together the butter, chocolate and cream in a large bowl set over a saucepan of barely simmering water. Remove from heat.
Meanwhile place the biscuits in a plastic freezer bag and crush with a rolling pin until fine crumbs. Fold the biscuit crumbs together with the ground almonds and the chocolate mixture. Stir in the rum.
Leave mixture to cool then take a small amount at a time to roll into a smooth ball the size of a walnut. Roll in the Cake Angels Disco Sprinkles, to decorate.
Refrigerate for a minimum of 2 hours. Pop into petite paper cases to serve.