01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
03 - In a large bowl, cream butter and sugar together with an electric mixer until light and fluffy, about 2 minutes.
04 - Beat in the eggs one at a time, then add vanilla extract, milk, and lemon zest; mix until smooth.
05 - Gradually add the dry ingredients to the wet ingredients, mixing just until combined.
06 - Divide the dough evenly into 3–4 bowls. Tint each portion with a different pastel food coloring, mixing until the desired shade is reached.
07 - Chill colored doughs in the refrigerator for 20 minutes to make handling easier.
08 - Scoop 1 tablespoon of dough, roll into a ball, then roll first in granulated sugar and then 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 the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.