Preheat oven to 350°F (175°C) and line baking sheets with parchment paper.

In a large bowl, cream together softened butter and granulated sugar until light and fluffy.

Add egg, lime zest, lime juice, and vanilla extract. Mix until well combined.

In a separate bowl, whisk together flour, baking powder, and salt. Gradually add to the wet mixture until a soft dough forms.

Scoop dough into small balls and roll in sugar if desired. Place 2 inches apart on baking sheet.

Bake for 10–12 minutes or until edges are lightly golden. Cool 5 minutes on the sheet before transferring to wire rack.

Optional: drizzle with a glaze made from powdered sugar and lime juice once cookies are cooled.