Beat butter and granulated sugar until light and fluffy, about 2-3 minutes.

Add egg and vanilla extract, mixing until smooth.

In a separate bowl, whisk flour, baking powder, and salt.

Gradually add dry ingredients to wet, mixing until dough forms.

Preheat oven to 350°F (175°C). Roll dough into balls and flatten on a parchment-lined baking sheet.

Bake for 8–10 minutes or until edges are lightly golden. Cool completely.

For frosting, beat butter until creamy. Add powdered sugar, peppermint extract, and milk until smooth. Tint pink if desired.

Frost cooled cookies and sprinkle with crushed peppermint. Let set before serving.