Key Lime Thumbprint Cookies
Makes about 60
FOR THE DOUGH
8 ounces (2 sticks) unsalted butter, softened
1/2 cup granulated sugar
2 large egg yolks, room temperature
1 teaspoon pure vanilla extract
2 1/2 cups all-purpose flour
1 teaspoon coarse salt
FOR THE FILLING
1 cup granulated sugar
3 tablespoons all-purpose flour
3 large eggs, room temperature
1 tablespoon finely grated Key lime zest (from 5 limes), or substitute regular limes
3 tablespoons fresh Key lime juice (from 12 Key limes), or substitute regular limes
1/4 teaspoon coarse salt
Confectioners' sugar, for dusting
Make the dough: Cream butter and granulated sugar with a mixer until pale and fluffy. Add yolks and vanilla, and beat for 1 minute. Reduce speed to low, and beat in flour and salt until combined. Cover, and refrigerate until firm, about 1 hour (or up to 1 day).
Make the filling: Preheat oven to 325 degrees. Whisk granulated sugar, flour, and eggs in a medium bowl. Stir in lime zest and juice and salt.
Roll balls using 2 teaspoons dough for each. Place 1 inch apart on parchment-lined baking sheets. With the handle of a wooden spoon, press gently in the center of each to create an indentation. Bake for 10 minutes. Press centers if indentations lose definition. Spoon filling into centers. Bake until cookies are light brown around edges, 6 to 8 minutes. Let cool on wire racks.
Cookies will keep, covered, for up to 2 days. Just before serving, dust with confectioners' sugar.