In the bowl of a stand mixer fitted with the paddle attachment, beat butter, confectioners’ sugar, and salt at medium speed until pale and creamy, 2 to 3 minutes, stopping to scrape bottom and sides of bowl. Add egg, and beat until combined, stopping to scrape paddle and bottom and sides of bowl. With mixer on low speed, gradually add flour, beating until just combined.

Shape dough into a disk, and wrap in plastic wrap. Refrigerate for at least 1 hour or up to 1 week, or freeze for up to 2 months. Let frozen dough thaw in refrigerator overnight before using.