Ingredients

• 1 cup (2 sticks) unsalted butter, at room temperature
• 1 cup sugar
• 1 tablespoon finely grated lime zest
• 1 tablespoon fresh lime juice
• 1 egg yolk
• 1/4 teaspoon salt
• 1 1/2 cups all-purpose flour

Instructions

1. Cream butter and sugar until fluffy. Beat in lime zest, juice, egg yolk, and salt. Stir in flour to make a medium dough. Form dough into a log about 2 inches in diameter. Wrap tightly in plastic wrap and chill for at least 2 hours, or until firm.
2. Preheat oven to 350 degrees F.
3. Cut 1/8-inch-thick slices from the dough log and transfer to ungreased cookie sheets. Bake in the center of the oven for 9 to 11 minutes, just until edges turn golden. Let cool on baking sheets for 1 minute, then remove to wire racks.