Cloyingly sweet, there are nevertheless a cookie that has been found in virtually every corner food shop in New York for decades. Purists demand both the black and white frostings, but some heretics prefer all black or all white cookies. “Pish!” say true New Yorkers.
The following recipe is adapted from Apt. 2B Baking Co and appears on food52.com and makes about 3 dozen 2 1/2-inch cookies.
For the cookies:
1 1/4 cups all purpose flour
1/2 teaspoon baking soda
1/2 teaspoon salt
1/3 cup buttermilk
1 teaspoon vanilla extract
6 tablespoons unslted butter
1/2 cup granulated sugar
1 large egg
Preheat the oven to 350F°. Line two baking sheets with parchment paper.
In a small bowl, whisk the flour, baking soda and salt together. In the bowl of a stand mixer, beat the butter and sugar until creamy.Add in the vanilla extract and egg and mix until well combined, Scrape down the bowl.
Alternately add in the flour mixture and buttermilk in three additions. Mixuntil just combined. Use a pastry bag [n.b.: works much better than the recipe’s alternate suggestion of a one tablespoon measure] to portion the cookies 1 inch apart onto the baking sheets.
Bake the cookies for 6 to 8 minutes, or until the tops spring back when pressed gently and the cookies are light golden brown around the edges. Cool completely.
For the icing:
1/12 cups 10X sugar, sifted
1 tablespoon light corn syrup, optional
2 teaspoons lemon juice
1/2 teaspoon vanilla extract
2 tablespoons water
1/8 teaspoon salt
1/4 teaspoon instant espresso powder
1/4 cup cocoa powder, sifted
Whisk the first 6 ingredients together until very smooth; you may need to add a bit more liquid or 10X sugar to achieve a spreadable consistency. Remove half of the mixture to a separate bowl and add the espresso and cocoa powders, blending until smooth. You will likely need to add a few drops of water to thin the chocolate frosting to a spreadable consistency.
Using an offset icing spatula, spread the vanilla icing on one half of the flat side of the cookies, the spread the chocolate on the other half. Let set for a few minutes before serving.
The cookies can be stored in an airtight container at room temperature for two days.