Lime Sugar Cookies

3/4 stick (6 tablespoons) unsalted butter, softened

2 tablespoons cold vegetable shortening

1 cup granulated sugar

1/2 cup lime sugar

1 large egg

1 teaspoon vanilla

1 1/4 cups all-purpose flour

1 teaspoon baking powder

1/2 teaspoon salt

Beat together butter, shortening, granulated sugar, and 2 tablespoons lime sugar with an electric mixer until light and fluffy. Beat in egg and vanilla. Sift flour, baking powder, and salt together over egg mixture, then beat on low speed until just combined.

Form dough into a 10-inch log (2 inches in diameter) on wax paper, then wrap in wax paper. Chill dough until firm, at least 4 hours.

Preheat oven to 375°F.

Remove wax paper and cut log into 1/4-inch-thick rounds. Bake cookies 1/2 inch apart on ungreased baking sheets in batches in middle of oven 10 to 12 minutes, or until pale golden. Immediately transfer with a metal spatula to a rack set over a sheet of wax paper and sprinkle tops with remaining lime sugar. Cool cookies.

Cooks�?notes:
Dough can be made 2 days ahead and chilled, wrapped well in plastic wrap.

Cookies keep in an airtight container at cool room temperature 2 days.

Makes about 36 cookies