For the Cookies:

1. Preheat oven to 350°F. Line baking sheets with parchment paper.
2. In large bowl, stir together the sugar and lemon zest until the sugar becomes moist and fragrant.
3. Add butter to the sugar and beat with an electric mixer until light and fluffy; about 3 minutes.
4. Add eggs, lemon juice, and vanilla and mix until combined.
5. In a medium bowl, whisk together the flour and baking powder.
6. Gradually add the flour mixture to the wet ingredients and mix until just combined.
7. Using a medium cookie scoop, (1 1/2 tablespoons), scoop cookie dough onto prepared baking sheets leaving 2 inches between each cookie dough ball.
8. Bake in preheated oven for 10-12 minutes, or until the bottoms of the cookies are golden. Allow cookies to rest on cookie sheet for 5 minutes before removing to a wire cooling rack to cool completely.
9. Once cookies have cooled completely, prepare the glaze.

For the Glaze:

1. In a small bowl, whisk together the confectioners’ sugar, lemon juice and milk.
2. Spoon or pipe glaze over cookies. If desired, immediately sprinkle cookies with sparkling sugar.  Allow glaze to harden before serving.