It doesn't qualify as a New York bakery if it doesn't have black-and-white cookies and in our house, it doesn't qualify as a New York Christmas Eve without some of these left out for Santa (along with some spiked eggnog). They're actually little cakes, but who's going to argue? Personally, I eat them this way: chocolate frosting, then the cookie part that was under the chocolate frosting; then the white frosting, then that cookie part. I'm not sure how Santa eats them, but I know he does, because there's never any left. This gluten-free version was inspired by Zabars. —wssmom
Test Kitchen Notes
There is an art to producing a good Black and White. I have tried before and until now have never found just the right recipe. The cookie has to be soft and cakelike and the icing can't be too runny or too thick. Wssmom's Black and White is the perfect cookie. It's light and moist and just the right texture and the icing stays where you put it so that you get that perfect line of chocolate and white and its smooth as silk. Santa must make a beeline to her house knowing what is waiting for him under or by the tree. This cookie is lighter than many bakery B&W's, and that makes it superior in my opinion. I highly recommend you give this a try, its simple to make and yields a really delicious cookie. —sdebrango
Preheat oven to 350 degrees. Using a hand mixer, cream together the butter, sugar, eggs and vanilla. Add the milk.
Sift together the dry ingredients, and gradually add to the butter-sugar mix. Stir in the lemon zest.
Line a baking sheet with parchment paper. Use an ice-cream scoop (don't fill it up all the way) to drop six largish circles of batter onto the baking sheet. Smush them down a bit in a circular motion with s spoon so you don't wind up with giant puffy cookies. Bake for 15 minutes or until they spring back when pressed. Remove from the oven, let them sit for five minutes on the baking sheet, then transfer to a wire rack. If some of the cookie bottom sticks to the parchment that's OK, because that means they won't be so tippy.
Prepare frosting: gather 2 cups powdered sugar, 1/4 cup plus one tablespoon boiling water, 1/2 ounce bittersweet chocolate, shaved. In a heavy saucepan, combine sugar and water until melted. Transfer half into a small bowl, set aside; add chocolate to the remaining half and stir over low heat until melted.
Frost the flat half of each cookie with white icing; the other half with brown icing. Serve with a New York attitude!