Preheat the oven to 350°F (175°C) and grease a baking sheet.

In a medium bowl, whisk together the flour, baking soda, and salt until combined.

In a separate bowl, beat the softened butter and granulated sugar until lighter in color and fluffy.

Mix in the egg, key lime juice, key lime zest, and vanilla extract until smooth.

Combine the dry ingredients with the wet in a few additions, mixing just until the dough comes together.

Drop rounded tablespoons of dough onto the baking sheet, leaving space between each.

Bake for 10–12 minutes until the edges are lightly golden and centers look soft.

Move cookies to a wire rack to cool completely before glazing.

In a small bowl, stir powdered sugar with key lime juice until preferred consistency is reached.

Drizzle the glaze over cooled cookies and let it set before serving.