250g butter, cubed, at room temperature
110g (3/4 cup) icing sugar, sifted
1 tsp vanilla essence
300g (2 cups) plain flour
30g (1/4 cup) cocoa powder
Extra icing sugar, for dusting
Preheat oven to 160°C. Line 2 baking trays with non-stick baking paper.
Use electric beaters to beat the butter, icing sugar and vanilla essence in a medium mixing bowl until just combined and smooth.
Sift together the flour and cocoa powder. Add to the butter mixture and use a wooden spoon and then your hands to mix into a smooth dough. Wrap in plastic wrap and place in the fridge for 10 minutes to rest.
Roll heaped teaspoonfuls of dough into balls and place onto lined trays. Pinch top half of each ball with three fingers to form a soft peak.
Bake in preheated oven for 7 minutes. Swap trays around and bake for a further 7 minutes or until cooked through. Stand for 5 minutes before transferring to a wire rack to cool. Dust with icing sugar just before serving.