01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together flour, baking powder, baking soda, and salt in a medium bowl. Set aside.
03 - Beat butter and sugar with an electric mixer until light and fluffy, about 2 minutes.
04 - Beat in eggs one at a time. Add vanilla extract, milk, and lemon zest; mix until smooth.
05 - Gradually add dry ingredients to wet ingredients, mixing just until combined.
06 - Divide dough evenly into 3-4 bowls. Tint each portion with different pastel food coloring until desired shade is reached.
07 - Refrigerate colored doughs for 20 minutes to make handling easier.
08 - Scoop 1 tablespoon of dough, roll into a ball, then roll first in granulated sugar and generously in powdered sugar.
09 - Place coated dough balls 2 inches apart on prepared baking sheets.
10 - Bake for 10-12 minutes or until cookies are cracked on top and just set at the edges.
11 - Cool on baking sheet for 5 minutes, then transfer to a wire rack to cool completely.