- Cream butter and sugar until light and fluffy. Beat in egg and pinch of salt, then gradually mix in flour. Divide dough into two portions and place each on a sheet of parchment paper or plastic wrap. Shape into logs about 2 inches in diameter and wrap tightly. Chill in refrigerator until firm, at least 1 hour.
- Preheat oven to 350 degrees. Line two baking sheets with parchment paper. On a sheet of waxed paper, combine 1½ teaspoons salt and sparkling sugar. Unwrap dough and roll in salt-sugar mixture to coat well. Cut each log into 1/8-inch-thick rounds, arranging them 1 inch apart on prepared baking sheets. Bake until lightly browned on edges, about 14-16 minutes, rotating pans halfway through. Remove to wire racks to cool completely. Cookies can be stored at room temperature in an airtight container for up to 1 week.