Step 1

Preheat oven to 180°C (160°C fan-forced). Grease oven trays, line with baking paper.

Step 2

Beat butter and sugar in medium bowl with electric mixer until light and fluffy. Transfer mixture to large bowl, fold in flours, rind, juice and nuts. Knead on floured surface until smooth.

Step 3

Roll level tablespoons of mixture into 15cm-long sticks, place sticks 3cm apart on trays.

Step 4

Bake shortbread about 20 minutes or until firm. Stand shortbread on tray 5 minutes, transfer to wire racks to cool.

Step 5

Pipe or drizzle melted chocolate onto shortbread.