1 teaspoon grated Key lime zest, plus 3 tablespoons Key lime juice (from about 5 key limes. OR use regular lime zest and 1½ tablespoons each lemon and lime juice)
4 (plus) drops green food coloring
½ cup confectioners' sugar, sifted
2 tablespoons green sanding sugar
Instructions
Whisk the flour, baking powder and salt in a medium bowl. Beat the butter and granulated sugar in a large bowl with a mixer on medium speed until light and fluffy, about 3 minutes. Add the eggs, one at a time, beating well after each addition. Beat in the lime zest and juice, then beat in the food coloring. Reduce the mixer speed to low; gradually add the flour mixture, beating until just combined. Cover and refrigerate until firm, about 45 minutes.
Position racks in the upper and lower thirds of the oven; preheat to 350 degrees F. Line 2 baking sheets with parchment paper. Combine the confectioners' sugar and sanding sugar in a small bowl. Roll tablespoonfuls of dough into balls and toss in the sugar mixture to coat completely. Arrange the cookies 2 inches apart on the prepared baking sheets.
Bake, switching the pans halfway through, until the cookies are puffed and cracked on top and lightly golden around the edges - start checking at 13 minutes. Let cool 5 minutes on the baking sheets, then transfer to racks to cool completely.
Recipe by The Amiable Cooks at https://theamiablecooks.com/key-lime-crackle-cookies/