Ingredients:
(Ingredients in parentheses are from the older version of the joy of cooking.)
Whisk together flour, baking powder, and salt. Separately, beat the butter and sugar on medium speed until very fluffy and well blended. Add the egg, vanilla, and lemon zest, and beat until well combined.
Stir the flour mixture into the butter mixture until well blended and smooth. Cover and refrigerate until slightly firm, 20 to 30 minutes. Place the dough on one end of a long sheet of wax or parchment paper. With lightly greased hands, shape into an even, 11-inch-long log. Roll up in the paper, twisting the ends of the paper to prevent unrolling. Place on a baking sheet and freeze until completely frozen, at least 3 hours. Use immediately or transfer to a sealable plastic bag and freeze for up to one month. (To make the pinwheel version, roll out two sheets of the dough, put one on top of the other, and then roll into a "pinwheel log").
To bake, position a rack in the upper third of the oven, and preheat to 375 degrees. Grease cookie sheets. Gently peel the paper off the log and cut the log crosswise into 1/8-inch-thick slices. Transfer the slices to the cookie sheets, spacing about 2 inches apart. Sprinkle a little bit of extra sugar on top, and press in lightly to make it stick. Bake, 1 sheet a time, until the cookies are golden all over and just slightly darker at the edges, 7 to 10 minutes. The longer the baking time, the crisper the cookies. Remove the sheet to a rack and let stand until the cookies firm slightly. Transfer the cookies to racks to cool.