Heat the oven to 200C/180C fan/gas 6. Beat the salted butter, vanilla and sugar together with an electric whisk until pale and fluffy. Sift over the flour and beat again until just combined. Spoon the dough into a piping bag fitted with a medium star nozzle.

Pipe the dough in small 5cm swirls on one large or two smaller baking trays lined with baking parchment, spacing them apart to allow for them to spread. Bake for 15-20 mins until pale golden.

Leave to cool on the trays for 5 mins, then transfer to a wire rack to cool completely.