Key Lime Meltaways

From Smitten Kitchen, adapted from Martha Stewart.  My kids were really into these.  I didn't use key limes.  We have both key lime and regular lime trees, and the regular one was producing.  I will probably try this with key limes later when we have a key lime harvest.

You could also keep the logs frozen for up to two months, and use them as the meltaway craving hits.

Yield: 5 dozen

12 tablespoons (1 1/2 sticks, 170 grams or 6 ounces) unsalted butter, room temperature
1 cup (120 grams) confectioners’ sugar
Grated zest of 4 tiny or 2 large key limes
2 tablespoons (30 ml) freshly squeezed lime juice
1 tablespoon (15 ml) pure vanilla extract
1 3/4 cup plus 2 tablespoons (235 grams) all-purpose flour (a.k.a. 2 cups minus 2 tablespoons)
2 tablespoons (15 grams) cornstarch
1/4 teaspoon fine sea or table salt

In the bowl of an electric mixer fitted with the whisk attachment, cream butter and 1/3 cup sugar until fluffy. Add lime zest, juice, and vanilla; beat until fluffy.

In a medium bowl, whisk together flour, cornstarch, and salt. Add to butter mixture, and beat on low speed until combined.

Between two 8-by-12-inch pieces of parchment paper, form dough into two 1 1/4-inch-diameter logs. Chill at least 1 hour.

Heat oven to 350 degrees. Line two baking sheets with parchment. Place remaining 2/3 cup sugar in a resealable plastic bag. Remove parchment from logs; slice dough into 1/4-inch-thick rounds. Place rounds on baking sheets, spaced 1 inch apart.

Bake cookies until barely golden, about 15 minutes. Transfer cookies to a wire rack to cool slightly, just three or four minutes.

While still warm, place cookies in the sugar-filled bag; toss to coat. Bake or freeze remaining dough. Store baked cookies in an airtight container for up to 2 weeks.