250g unsalted butter, chopped, room temperature
1 cup icing sugar mixture
3 tsps vanilla bean paste
1 and a 1/2 cups plain flour
3/4 cup rice flour
1/4 cup cornflour
3/4 cup finely chopped pistachios
1 and a 1/2 cups White Choc Melts
Grease a 19cm x 30cm lamington pan. Line the base and sides with baking paper. Extend the paper 3cm above the pan edges.
Beat butter, sugar, and vanilla in a small bowl of an electric mixer until light and fluffy. Move to a large bowl. On low speed, beat in sifted flours and 1/2 cup pistachios until combined.
Using floured fingertips, spread the mixture over the base of the prepared pan. Smooth over top. Refrigerate for 15 minutes. Using a sharp knife, score dough into 24 equal fingers.
Cook in a moderately slow oven (160C) for about 30 minutes, or until lightly golden. Remove from oven. Gently cut through score marks to the base of pan. Cool in pan.
Using baking paper, lift shortbread from pan onto a board. Gently cut through score marks again to separate shortbread fingers.
Melt chocolate in a heatproof bowl sitting over a saucepan of simmering water. Stir until smooth. Transfer to a small jug.
Dip one end of the shortbread into chocolate one by one. Sprinkle with the rest of the pistachios. Place on a baking paper lined tray. Stand at room temperature until set.