01 -
Beat the softened butter and icing sugar together until smooth and creamy. Stir in the finely grated orange zest.
02 -
Mix flour and salt, then add to the butter mixture with the chopped pistachios. Mix just until the crumbs begin to hold together; press gently into a dough without kneading.
03 -
Shape the dough into a log about 20 cm long and 4–5 cm across. Wrap and chill for at least 30 minutes until firm enough to slice neatly.
04 -
Heat oven to 170°C / 340°F. Line a large baking tray with parchment. Cut the chilled log into 20 rounds, each about 1 cm thick, and place with a little space between them. Press any cracked edges back together.
05 -
Bake for 15–18 minutes until the edges are pale golden and the surfaces look set. The shortbread will still feel delicate when hot; do not bake until dark brown.
06 -
Leave on the tray for 10 minutes, then move carefully to a rack for at least five more minutes. Serve once firm; longer cooling makes the crumb crisper.
07 -
Store completely cooled shortbread airtight in a cool dry place for up to five days. Freeze in a sealed container for up to two months and thaw covered at room temperature.