1. Beat the butter and sugar with an electric mixer until creamy. Add the egg yolk and vanilla and beat until combined. Add the flour and knead until the dough is just smooth. Shape into a flat disk, wrap in baking paper and refrigerate for 30 minutes to rest.
2. Preheat the oven. Roll out the dough thinly (about 5mm) with a rolling pin – dust your work surface with a little flour to prevent the dough from sticking to it. Press out your desired shapes and arrange the cookies on baking trays lined with baking paper. Repeat with all the dough.
3. Bake for 8–10 minutes or until lightly browned and done.
Cool on a wire rack and store in an airtight container.