Lemon and lime shortbread

Preheat oven to 160°C. Line 2 oven trays with baking paper. Put butter, sugar and vanilla in the bowl of an electric mixer and beat until light and creamy. Stir in lemon zest and lime zest.

Sift flour over butter mixture. Add semolina and stir until well combined and a soft dough forms.

Turn out dough onto a lightly floured surface and knead until smooth.

Roll out dough between 2 sheets of baking paper to 5mm thick. Using star-shaped biscuit cutters, cut shapes from dough. Use a chopstick to make holes in centre of stars, if desired. Transfer to prepared trays, spaced 2cm apart. Bake for 15 minutes or until firm to the touch. Cool completely on trays. Thread holes with ribbon, if using. Dust with icing sugar. Serve.