1. Prepare the oven. Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.

2. Cream the butter and sugar. In a large bowl, beat the softened butter and powdered sugar for 2–3 minutes until pale and fluffy.

3. Add the egg and vanilla. Beat in the egg and vanilla extract until smooth and well combined.

4. Mix the dry ingredients. In a separate bowl, whisk together the flour and salt. Gradually add the mixture to the butter mixture, stirring until a soft dough forms. If the dough is too stiff to pipe, add milk 1 teaspoon at a time.

5. Chill the dough. Refrigerate for about 30 minutes to help the cookies hold their shape during baking.

6. Shape the cookies. Transfer the dough to a piping bag fitted with a large star tip. Pipe small circles, rosettes, or S-shaped designs onto the prepared baking sheets. Alternatively, roll the dough into small balls and flatten slightly.

7. Decorate. Sprinkle lightly with coarse sugar or festive sprinkles, if desired.

8. Bake. Bake for 10–12 minutes, until the edges are just beginning to turn golden. The centers should remain pale.

9. Cool. Leave the cookies on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely and crisp up.