Chef John's Rosemary Shortbread Cookies

Instructions

• Preheat oven to 300 degrees F (150 degrees C). Line a baking sheet with parchment paper.
• Place cold butter, sugar, rosemary, salt, and vanilla extract in bowl. Combine with the back of a spatula or spoon, slowly incorporating ingredients together until butter has softened somewhat and ingredients come together.
• Pour flour into bowl with butter mixture. Flour your hands to then incorporate flour into the butter, using fingertips and rubbing mixture together until flour-y crumbs become buttery crumbs, 1 to 2 minutes. Press mixture together into a dough ball.
• Transfer dough to lightly floured work surface. Press dough into a disk, then into a 1/2-inch thick rectangle. Cover with a piece of plastic wrap. Flatten dough to 1/4-inch thick using a flat pan or rolling pin. Reshape into a rectangle.
• Cut dough lengthwise into 5 even strips about 1 inch wide, trimming extra dough if necessary. Cut each strip into 6 evenly sized squares. (You can roll out scraps to form more cookies if necessary). Transfer cookies to prepared baking sheet. Sprinkle each cookie with about a pinch of sugar. Using a fork, poke 4 rows of holes into each cookie.
• Bake in preheated oven until golden brown, about 50 minutes.
• Cool cookies 10 minutes on sheet; transfer cookies to rack to cool completely.