In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugar at medium speed until combined and creamy, 3 to 4 minutes, stopping to scrape sides of bowl. Beat in egg until combined, stopping to scrape sides of bowl. With mixer on low speed, gradually add flour and salt, beating until just combined.

Turn out dough onto a lightly floured surface, and shape into a disk. Wrap in plastic wrap, and refrigerate for at least 1 hour or up to overnight.