Black and Mocha Cookies (dairy)

Nussbaum and Wu, the erstwhile Morningside Heights bakery cafe (it's now Wu + Naussbaum and serves dumplings), used to serve this take on the New York classic black and white cookie: the black and mocha, which flavors the plain-vanilla side of the classic cookie with a shot of coffee flavor. Here's how to make the oversized iced cookies at home.

This post is part of the Eating New York series.

First things first, let's establish what a black and white type cookie must, and also importantly, must not, be. We're not going to get into the contested origin story of this baked good or discuss why it is (or, as some contrarians insist, isn't) a New York City food. It is, because you can find it, albeit in an insipid, paltry incarnation, in every deli and bodega, as well as whatever upscale bakery is trendy this week. Key features of this New York eat:

1. It's not really a cookie, it's actually a cookie-shaped cake.
2. It must be oversized, like the size of a saucer.
3. It's the flat side that gets iced.
4. The icing must crinkle when you bite into it, because it's dry on top but still has a little give underneath.
5. It has to have two flavors of icing split straight down the center: classically speaking, chocolate (black) and vanilla (white).

As any tri-stater worthy of the name knew well before Seinfeld explained it to America, the raison d'etre of the black and white is to provide you with the opportunity for dual-flavored bites.

The proper cross section and crumb of a black and white cookie.

Cakey cookie batter that's piped

The secret to getting the correct black and white cookie shape? These cookies must be piped. I tried about eleven times, and that's only a slight exaggeration, before I figured it out. Many, many authoritative sources will tell you to use an ice cream scoop. It doesn't work. If you use cake flour, which you want to do, because black and whites are actually little cakes, then the batter is too loose to be scooped. When you bake it, no matter how pedantically you follow the recipe, the scoops will start to look like perfect balck and whites about three to four minutes in...then spread into oblivion by the end of the baking time, forming a flat pancake of delicious, but otherwise useless, cookie dough. If you ditch the cake flour and go with all-purpose, your cookies will be the wrong texture and they'll stay too heaped, never attaining the proper shape. Piping the batter, for reasons that I suspect involve surface tension but I'm just not committed enough to chemistry to actually look up, ensures that the cookies spread to the requisite size in perfect, domed circles.

To mix the dough, you'll need to schlep out three small bowls, one for the dry goods, one to beat the eggs in, and yet another for the liquids. It's worth it, I promise. Sous chefing your ingredients means you can easily cream the butter with sugar, drizzle in the eggs, then alternate the dry and wet ingredients. So the dough comes together quickly and doesn't need chilling.

To pipe the dough, set up a piping bag with the largest round tip (or snip off the end). The entire batch of batter will easily fit in a standard-sized piping bag, so you don't need to refill. Beginning with the outer edge of the circle, pipe a 3" / 8 cm perimeter, end touching. Then, fill it in by spiraling the tip. If your finished circle has a pointy tip at the center like a cupcake, pat it down with your finger.

Icing black and white type cookies

The icing for black and whites is definitely a goldilocks situation: you want it to be thin enough to coat the cookie evenly, but not so thin it drips off. A bit of corn syrup lends it the characteristic crinkle and gloss, while leaving it moist underneath, as you can see from my finger imprints in the top left photo above. Once you have the right consistency, it's not too tricky to get a nice, neat line between the two icings. You can use either a spoon or a small icing spatula to drip the line down the middle, then fill in the rest. I found the spoon to work best, actually, although both work well.

The best video I found showing the icing technique is this one from the New York Times (it's queued up to start right at the icing part for you), which I mostly agree with (often vehemently) but naturally have some quibbles, too, namely: the cookie scoop method does not work.

To get the mocha flavor of the Nussbaum & Wu version (well, the non-chocolate half), you just need to dissolve a teaspoon of instant espresso powder into hot water before combining it with the powdered sugar.

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Black and Mocha Cookies (dairy)

The classic New York black and white cookie in a mocha and chocolate version, just like they used to sell at Nussbaum & Wu in Morningside Heights.

Course Dessert

Cuisine American

Prep Time 45 minutes

Cook Time 15 minutes

Ingredients

For the cookies:

• 2 cups cake flour - 245 g
• 1 tsp baking powder
• ¼ tsp kosher salt
• ⅓ cup buttermilk - 80 ml
• 1 tsp vanilla extract
• ½ cup butter - 110 g / 1 stick
• ⅔ cup granulated sugar - 135 g
• 2 eggs - at room temperature

For the mocha icing:

• 2 cups powdered sugar, sifted - 250 g
• 1 Tbsp hot water - 15 ml
• 1 tsp instant espresso powder
• 2 tsp light corn syrup or glucose - 10 ml
• ½ tsp vanilla extract

For the chocolate icing:

• 2 cups powdered sugar, sifted - 250 g
• 3 Tbsp cocoa powder - 22 g
• 1 Tbsp hot water - 15 ml
• 2 tsp light corn syrup or glucose - 10 ml
• ½ tsp vanilla extract

Instructions

Set up for mixing the dough:

• Preheat the oven to 375°F. Line two baking sheets. Prepare a large piping bag with a large, round tip and place it in a tall glass.
• In a small bowl, whisk together the all-purpose and cake flours, baking powder, and salt.
• In another small bowl, mix together the milk, 1 teaspoon vanilla, and lemon zest, if using.
• In a third small bowl, crack the eggs and beat well.

Make the batter:

• In a stand mixer fitted with the paddle attachment, beat together the butter (or shortening) and granulated sugar on medium speed until creamy and smooth, 3-4 minutes.
• Lower the speed to medium-low and pour in the beaten eggs in a slow stream.
• When the eggs are fully incorporated, add in the milk mixture. The batter will appear to curdle; this is okay, it'll soon come back together.
• With the mixer on low, slowly add in the flour mixture, beating until just combined.

Pipe the cookies:

• Wipe the batter into the piping bag. Pipe the batter in 3" / 5 cm circles, leaving plenty of space between each cookie.

Bake the cookies:

• Bake for 15 minutes, until light golden at the edges and well set.

Ice the cookies:

• First make the mocha icing: Begin by mixing the espresso powder into the tablespoon of hot water until fully blended. Add to the a medium mixing bowl along with the remaining ingredients. Whisk vigorously to combine. The icing should be the consistency of thick molasses. If it is too thick, add more hot water, no more than a few drops at a time.
• Ice completely cooled cookies on one side by using the back of a spoon to create a smooth line down the center. Fill in the rest of the cookie half and place on a lined sheet pan or cooling rack to set.
• In the meantime, make the chocolate icing: Combine all the ingredients in a second medium mixing bowl and whisk vigorously to combine. The chocolate icing will be thicker and you will likely need to add a few drops of water. Remember to add just a few drops at a time, as the consistency of the icing changes very quickly.
• When the mocha icing is completely hardened, lift the cookie by the mocha side and use another spoon to draw a straight line down the center of the cookie. Fill in the unglazed half with chocolate icing. Place back on the sheet pan or cooling rack to set.