In a mixing bowl, combine butter, Parmesan cheese, and rosemary. Mix until smooth and creamy.

Gradually incorporate flour, salt, black pepper, and optional lemon zest until a cohesive dough forms.

Wrap the dough in plastic wrap and chill in the refrigerator for at least 30 minutes.

Roll the chilled dough out on a floured surface to about 1/4 inch thick. Cut into shapes using snowflake cookie cutters.

Place cookie cutouts on a baking sheet lined with parchment paper. Chill again for 10 minutes.

Preheat oven to 350°F (175°C) and bake cookies for 12 to 15 minutes until edges are golden brown.

Let cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.