Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or silicone baking mat and set it aside.
In a medium bowl, whisk granulated sugar, lime zest and salt together. Add melted butter, lime juice, vanilla and eggs. Whisk to combine until all the ingredients are fully integrated.
In a medium bowl, whisk together the all-purpose flour and baking powder.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. The dough will be quite sticky.
Add a few drops of green food coloring to the dough and mix until the desired shade of green is achieved. You can add more food coloring if needed.
Cover with plastic paper and let the dough chill in the fridge for at least 4 hours.
Once cooled, place the powdered sugar in a shallow bowl or plate. Scoop out tablespoon-sized portions of dough and roll them into balls. Roll each ball in the powdered sugar until fully coated.
Arrange the coated dough balls on the prepared baking sheet, spacing them about 2 inches apart.
Bake for 10 minutes, or until the edges are set and the cookies are slightly puffed. The centers will still be slightly soft.
Remove the cookies from the oven and allow them to cool on the baking sheet for 5 minutes.
While the cookies are still warm, carefully press one heart shaped candy into the center of each cookie.Then transfer them to a wire rack to cool completely.
Once the cookies are completely cooled, serve and enjoy!