To ensure that the cookies are the same size, roll the logs so that they have a diameter of 1¼ inches. Letting the dough warm to room temperature in step 4 ensures that the cookies will spread evenly; if the dough is cold, the bottoms will spread more than the tops during baking. For slightly darker cookies with butterscotch notes, substitute brown sugar for granulated. The vanilla extract may be replaced with 1 teaspoon of your favorite extract. Tightly wrapped dough logs can be refrigerated for up to three days or frozen for up to two months. Thaw in the refrigerator for at least 6 hours before slicing. These cookies are delicious as is but you can also use this dough to make Pistachio-Apricot Slice-and-Bake Butter Cookies , Cherry-Almond Slice-and-Bake Butter Cookies , Raspberry-Cinnamon Slice-and-Bake Butter Cookies , Chocolate-Striped Ginger Slice-and-Bake Butter Cookies , and Mocha-Peppermint Mosaic Slice-and-Bake Butter Cookies .

Whisk flour, salt, and baking powder together in bowl. In second bowl, whisk melted butter, sugar, egg yolk, and vanilla until very smooth. Add flour mixture and stir with rubber spatula until well combined (dough will be loose). Let dough rest until firm, about 5 minutes.

Divide dough in half and roll each half into log that is 1¼ inches in diameter and about 10 inches long. Wrap logs tightly in plastic wrap and refrigerate until firm, at least 1 hour or up to 3 days.

Adjust oven rack to middle position and heat oven to 350 degrees. Let chilled dough sit on counter to soften slightly, about 15 minutes. Line 2 rimmed baking sheets with parchment paper.

Slice logs into ¼-inch-thick rounds and space 1 inch apart on prepared sheets. Let rest at room temperature for 10 minutes. Bake cookies, 1 sheet at a time, until edges are just golden, 10 to 12 minutes, rotating sheet halfway through baking.

Let cookies cool on sheet for 10 minutes, then transfer to wire rack and let cool completely, about 30 minutes. Serve. (Cookies can be stored at room temperature for up to 10 days.)

How to Shape Cookie Dough into a Log