250 g unsalted butter, chopped, at room temperature
½ cup caster sugar
1 tsp vanilla bean paste
1¾ cups plain flour
¼ cup custard powder
plain flour, for dusting
¾ cup dark chocolate melts
⅓ cup finely chopped unsalted pistachios
- Lightly grease two oven trays. Line with baking paper.
- Beat butter, sugar and vanilla with an electric mixer until light and fluffy. Add combined sifted flour and custard powder in two batches, beating on a low speed until just combined. Turn out mixture onto a lightly floured bench. Divide in half. Shape halves into flat discs. Wrap in plastic wrap. Refrigerate for 30 minutes.
- Roll out each half between two sheets of baking paper until 1cm thick. Using an 8½cm fluted round cutter, cut out 14 rounds, re-rolling dough. Using a 3cm fluted round cutter, cut out centres from each round. Place 3cm apart on trays.
- Cook both trays in a moderate oven (180C) for 15 minutes, or until light golden brown. Cool on trays.
- Melt chocolate in a heatproof bowl over a saucepan of simmering water. Spoon into a snap-lock bag. Squeeze into one corner. Twist bag and snip tip of corner.
- Drizzle chocolate over biscuits. Sprinkle with pistachios. Stand at room temperature until set.