01 -
In a medium bowl, sift together the flour, baking soda, cornstarch, and salt. Set aside. Zest the lemon into a small bowl.
02 -
Using a mixer, beat the butter and sugar on high speed for 2 minutes until soft and pale. Scrape down the sides of the bowl with a rubber spatula to ensure everything is well mixed.
03 -
Add in the lemon zest, lemon juice, and egg. Mix on medium until everything is combined. Make sure to scrape the bowl again to incorporate all the butter. If using, add about 2 drops of yellow gel food dye for a sunny color.
04 -
Add the dry ingredients to the wet mixture and mix on low speed just until combined. Fold in the white chocolate chips gently. Let the dough rest for 10 minutes to prevent too much spreading.
05 -
Preheat the oven to 350°F and line two cookie sheets with parchment paper. Place the granulated sugar in one small bowl and the powdered sugar in another.
06 -
Using a small cookie scoop (1 tablespoon), scoop the dough and roll each ball first in the granulated sugar, then generously in the powdered sugar for a thick coating. Place 12 cookies per sheet.
07 -
Bake for 8-10 minutes, just until the edges are set but the centers still look soft. Don't overbake or they'll dry out and the powdered sugar will melt completely.
08 -
Let the cookies cool on the hot pan for 5 minutes before transferring to a cooling rack to finish cooling completely.