Beat butter and sugar in a small bowl with an electric mixer until light and fluffy. Transfer mixture to a medium bowl; stir in combined sifted flour and malt powder, condensed milk, vanilla, melted chocolate and choc bits; mix well.
Roll heaped teaspoons of mixture into balls; place, about 5 cm apart, onto baking paper lined oven trays.
Cook in a moderate oven, 180c, for about 10 minutes, or until just firm. Stand biscuits on trays for 5 minutes; transfer to a wire rack to cool.
Drizzle biscuits with extra melted chocolate; stand until set.