Iced Lime Cookies

1/4 cup plus 2 tablespoons fresh lime juice plus 2 tablespoons grated lime zest
3/4 cup (1-1/2 sticks) unsalted butter, softened
2-1/4 cups sifted all-purpose flour
1-1/2 teaspoon cream of tartar
1 teaspoon baking soda
1/2 teaspoon salt
1/4 cup vegetable shortening
1-1/2 cups granulated sugar
2 large eggs
3/4 cup confectioners' sugar

Heat oven to 350 degrees and place rack in center. Line a baking sheet with parchment paper; set aside.

In a small saucepan, heat 1/4 cup juice over medium-high heat; simmer until reduced by half, about 4 minutes. Remove from heat, add 1/4 cup butter and let stand, stirring occasionally, until butter is melted and mixture is cooled, about 10 minutes.

In a medium bowl, combine flour, cream of tartar, baking soda and salt; set aside.

In a mixer bowl, beat together the remaining 1/2 cup butter, the shortening and granulated sugar on medium speed, scraping down sides of bowl occasionally, until light and fluffy, about 3 minutes. Add lime-butter mixture, eggs and zest; beat until combined. Reduce speed to low; add flour mixture and beat until combined. Cover bowl with plastic wrap and refrigerate until dough is firm enough to handle, about 1 hour.

Roll dough into 1-1/2-inch balls and place, 2-inches apart, on prepared sheet. Bake until light golden brown around edges, 14 to 16 minutes. Transfer sheet to a wire rack and let cool slightly. Transfer cookies to rack and let cool completely.

FOR ICING - In a small bowl, stir together confectioners' sugar and remaining 2 tablespoons juice until smooth. Drizzle over cookies and let stand until set, about 5 minutes.

Makes about 24 cookies

Store in an airtight container at room temperature, in single layers separated by waxed paper, up to 3 days.