Put the sugar in a bowl and add the finely grated orange zest. Rub together with your hands to help release the oils.

Add the flour and cold, cubed butter and rub together until you have an even crumb.

Add 1 tbsp of cold water and cut through with a cutlery knife. Give a little bit of the mixture a squeeze. If it comes together, it’s ready. If it’s dry and sandy, cut in up to another 1 tbsp cold water.

Gather up the dough and knead together only as much as it takes to get a smooth ball of dough.

Roll the dough into a cylinder with a length of 30cm (12 inches) and a diameter of 5cm (2 inches). Wrap in greaseproof paper or plastic wrap and place in the fridge to rest and chill for 15 minutes.

While the dough chills, preheat the oven to 170C (150C fan / 340F).

Slice the dough into 1 cm cookies.

Place them on a lined baking tray and prick each one a few times with a fork.

Bake for 20-25 minutes until they've taken on just a very slight golden colour.