How to Make It
In a food processor, combine all of the ingredients except the rosemary and salt. Pulse until a crumbly dough forms. On a lightly floured surface, form the dough into a log 1 1/2 inches in diameter. Wrap in plastic and chill until firm, about 1 hour.
Meanwhile, preheat the oven to 350°. Line 2 baking sheets with parchment paper. In a mortar, pound the rosemary with the salt until blended.
Using a thin, sharp knife, slice the dough into 1/8-inch-thick rounds. Arrange the sables 2 inches apart on the baking sheets. Bake in the middle and lower thirds of the oven for 12 to 15 minutes, until golden; shift the pans from top to bottom and front to back halfway through baking. Sprinkle the hot sables with the rosemary salt and let cool on the sheets for 5 minutes. Transfer the sables to a rack to cool completely.