This dough also makes a good filled cookie, or rich drop cookie; see About Drop Cookies or About Filled Cookies.

Whisk together in a medium bowl:

Beat in a large bowl, or in a stand mixer with the paddle attachment, until fluffy:

Add and beat until combined:

Stir the flour mixture into the butter-sugar mixture until blended. Shape the dough into an even 11-inch-long log and wrap tightly in parchment paper. Refrigerate or freeze until firm.

Preheat the oven to 375°F. Grease or line 2 baking sheets or cookie sheets with parchment paper.

Cut the log into scant ¼-inch-thick slices and arrange about 1 inch apart on the prepared baking sheets. Bake until the cookies are lightly browned, 8 to 10 minutes, switching oven racks and rotating the sheets halfway through. The longer the baking time, the crisper the cookies. Let cool on the sheets for 2 to 3 minutes, then transfer to a wire rack to cool completely.