1 cup unsalted butter
3/4 cup granulated sugar
1/4 teaspoon salt
2 teaspoons pure vanilla extract
1 large egg yolk
2 cups all-purpose flour
Beat the butter, sugar, salt and vanilla together until smooth and creamy. Mix in the egg yolk until well incorporated, scraping down the sides of the bowl at least once. Add the flour and mix just until incorporated. Scrape onto a lightly floured board and knead a few times to smooth out the dough, taking care not to overwork. Turn onto a sheet of plastic wrap and roll into a log, wrap up and refrigerate for several hours.
Preheat the oven to 325°F. 7 Line baking sheets with parchment. Slice the dough into slices about 1/8″ thick or roll the dough out and cut with cookie cutters. Place cookies on sheet about an inch apart. Bake until JUST beginning to turn golden around the edges, about 16-17 minutes.