•1 cup flour
•1/2 cup corn starch
•1/2 cup confectioners' sugar
•3/4 cup (1-1/2 sticks) butter, cut into cubes
•1 teaspoon grated lime zest
•1 teaspoon key lime juice
•1 cup white chocolate chips
•1/4 cup chopped macadamia nuts (optional)
•Additional confectioners' powdered sugar for coating (about 1 cup)
Line cookie sheets with parchment paper or Silpat baking pad.
In a small bowl, combine flour, corn starch, and confectioners' sugar. Set aside.
In a large bowl, cream butter, key lime juice, and key lime zest until smooth.
Add flour mixture to butter mixture and begin mixing on low speed. Once mixture begins to get thick, increase speed to thoroughly mix until combined, scraping down sides. The dough should eventually come together into almost a dough. Scrape batter from beaters. Mix in white chocolate chips and optional macadamia nuts with a large spoon.
Refrigerate dough for 45 minutes to firm up. (It is important that the dough be very cold before going into the oven or they will spread.) When ready to bake, preheat oven to 350 degrees F.
Roll dough into 1-inch balls. Place 1-1/2 inches apart on lined baking sheet, and bake for 10 to 12 minutes until bottom edges just barely begin to turn brown. Do not over-bake. Let cool on baking sheets for at least 5 minutes, then remove to racks to cool.
Pour powdered sugar into a bowl. Roll key lime cookies in powdered sugar to cover.Let cool and roll again in powdered sugar. Store in an airtight container.