I spent the first two years of my time in New York city looking for the perfect black and white cookie. It was a mission bordering on obsession. The black and white cookie is nearly ubiquitous throughout the five boroughs, and there are many versions to be found in the various delis, bakeries, and even grocery stores. The black and white is, in my book, the official cookie of New York City. Though this honor is probably not recognized by any city agency, it is assumed, and that status is duly protected by the citizens. In fact, the merits of the various versions of the cookie are so heavily debated among devotees that we were nervous about supporting any one recipe. In the end, we went with a fairly straightforward adaptation: cakey vanilla cookie, thin layer of vanilla (white) frosting and thin layer of chocolate (black) frosting.
In a large bowl, sift together the flour, baking soda, baking powder, and salt.
In the bowl of a standing mixer fitted with the paddle attachment, cream the butter and sugar until fluffy, about 2 minutes. Scrape down the bowl and add the eggs and egg yolk one at a time, beating briefly after each addition. Scrape down the sides and bottom of the bowl again, and mix on low speed for 10 seconds. Add the flour mixture in three parts, alternating with the buttermilk in two parts (end with the flour mixture). Scrape down the bowl; add the vanilla and lemon zest, and mix on low speed for a few more seconds.
Using a ¼-cup ice cream scoop, drop the dough onto the prepared baking sheets, leaving about 3 inches around each cookie. (You’ll be able to fit about 6 cookies onto each sheet.)
In a large bowl, whisk together the confectioners’ sugar, milk, cream, and vanilla. If the mixture is too thick, add milk by the teaspoon until the desired consistency is reached. Pour half of the frosting (about ¾ cup) into a separate bowl and add the cocoa powder and 1 teaspoon water. Stir to incorporate the cocoa powder. The chocolate frosting should be about the same consistency as the “white” frosting. If it is too thick, keep adding water by the teaspoon until you get the right balance.
Use an offset spatula to spread white frosting on half of the flat side of each cookie. Let stand until almost set, about 20 minutes. Clean the spatula and use it to spread chocolate frosting over the unfrosted half of each cookie. (If the frosting thickens up while you are working, whisk it until it loosens.) Let the frosted cookies set completely, about 1 hour, before serving them.
Black and White Cookies are essentially little cakes, and they taste best eaten the day they are made. However, you can store them in an airtight container for up to 3 days at room temperature.
© 2010 All rights reserved. Published by Abrams Books.