2 tablespoons cornstarch
2/3 cup key lime juice
3/4 cup sugar
2 large egg yolks
1 cup butter, softened
1/2 cup confectioners' sugar
1/8 teaspoon salt
1 teaspoon vanilla extract
1/2 teaspoon coconut extract
2 cups all-purpose flour
2 large egg whites
2 teaspoons water
2-1/2 cups sweetened shredded coconut
4 ounces white baking chocolate, chopped
1 tablespoon shortening
1. For lime curd, in a small saucepan, whisk cornstarch and lime juice until smooth. Whisk in sugar and egg yolks; cook and stir over medium heat until boiling. Transfer to a bowl; cool slightly. Press plastic wrap onto surface of curd; refrigerate until cold.
2. Preheat oven to 400°. Cream butter, confectioners' sugar and salt until light and fluffy. Beat in extracts. Gradually beat in flour.
3. In a small bowl, whisk together egg whites and water. Place coconut in a separate bowl. Shape dough into 1-1/4-in. balls. Dip in egg whites, then roll in coconut, coating well. Place 2 in. apart on parchment paper-lined baking sheets. Press a deep indentation in center of each with the handle of a wooden spoon.
4. Bake until edges are golden brown, 12-14 minutes. Reshape indentations as needed. Cool on pans 5 minutes. Remove to wire racks to cool completely.
5. To serve, fill each cookie with about 1-1/2 teaspoons curd. In a microwave, melt white chocolate and shortening; stir until smooth. Drizzle over cookies. Refrigerate leftover filled cookies. Makes about 2 1/2 dozen.