01 - Preheat 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 electric mixer until light and fluffy, approximately 2 minutes.
04 - Beat in eggs one at a time. Add vanilla, milk, and lemon zest; mix until smooth.
05 - Gradually add dry ingredients to wet mixture, 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 firm for easier handling.
08 - Scoop 1 tablespoon dough, roll into ball. Roll first in granulated sugar, then generously coat in powdered sugar.
09 - Place coated dough balls 2 inches apart on prepared baking sheets.
10 - Bake for 10-12 minutes until tops are cracked and edges are set.
11 - Let cool on baking sheet for 5 minutes, then transfer to wire rack to cool completely.