Step 1In a large bowl, stir together the flour, salt, lemon zest and rosemary.
Step 2In another bowl, vigorously beat the butter and sugar using a wooden spoon until creamy and lightened in color, about 3 minutes. (Alternatively, you can use a stand mixer fitted with the paddle attachment.) Add the flour mixture and mix just until combined. Gather the dough into a ball, wrap tightly in plastic wrap, and refrigerate for 30 minutes.
Step 3About 15 minutes before you’re ready to bake the cookies, heat the oven to 300 degrees and line a baking sheet with parchment paper.
Step 4On a lightly floured surface, roll out the dough to 1/2-inch thickness. Cut into 20 rectangles (or any shape you like) and place them on the prepared baking sheet, leaving space between each one. Bake until lightly golden brown, 30 to 35 minutes, rotating halfway through for even coloring. Transfer to a wire rack and cool completely. Store the cookies in an airtight container for up to 1 week.