Preheat oven to 350°F.
In a small bowl, whisk together the flour, baking powder, baking soda and salt. Set aside.
In a mixing bowl, combine granulated sugar with lime lest, pressing zest into sugar with your fingers. Mix in confectioners sugar. Add butter and cream until fully incorporated.
Beat in egg and lime juice.
Mix in the flour mixture just until fully incorporated.
Shape into balls, approximately 25 g. each (about 1 tbsp.), and place on cookie sheets at least 2 inches apart. Refrigerate for at least 15 minutes.
Meanwhile, make the coating: Combine granulated sugar with lime lest, pressing zest into sugar with your fingers. Whisk in confectioners sugar. Roll warm cookies in mixture.
Bake for 11-12 minutes. The bottoms should be lightly browned.
Allow to cool for 1 to 2 minutes. Using a metal spatula, carefully roll each cookie in the coating while they are still warm. Allow to cool completely on wire rack.