Drop-Cake Black and White Cookie
Afternoon Nosh at the Bakery Case
The black and white is a drop cake masquerading as a cookie. Built on a base of sifted supermarket cake flour, these tender, buttermilk-laced rounds match the exact texture you expect behind the deli glass case. We skip the commercial fondant for a clever corn syrup glaze that sets with a crackly crust while staying perfectly soft underneath, so grab an offset spatula and lay the vanilla side down first before the icing snaps.
Ingredients
- all-purpose flour1 3/4 cup
- cornstarch1/4 cup
- baking powder1/2 tsp
- baking soda1/2 tsp
- kosher salt1/2 tsp
- unsalted butter1/2 cup
- granulated sugar1 cup
- large egg1 large
- full-fat buttermilk1/3 cup
- pure vanilla extract2 tsp
- lemon zest1/2 tsp
- confectioners' sugar4 cup
- boiling water3 tbsp
- light corn syrup2 tbsp
- pure vanilla extract1 tsp
- Dutch-process cocoa powder3 tbsp
- instant espresso powder1 pinch
Method
- 01
Preheat the oven to 350°F and line two baking sheets with parchment paper.
In a medium bowl, whisk together the flour, cornstarch, baking powder, baking soda, and salt. This cornstarch trick dilutes the gluten, mimicking the delicate structure of commercial bakery cake flour.
- 02
Cream the butter and granulated sugar until exceptionally pale and fluffy.
Beat them in a stand mixer on medium-high speed for a full three to four minutes. Beat in the egg, scraping down the sides of the bowl, then mix in the two teaspoons of vanilla extract and the lemon zest.
- 03
Alternate adding the dry ingredients and buttermilk to the butter mixture.
To prevent a tough, bread-like cookie, add the dry ingredients in three additions, alternating with the buttermilk in two. Mix on the lowest possible speed until just combined; the batter will resemble a thick cupcake batter.
- 04
Scoop the batter onto the baking sheets and gently smooth the tops.
Use a two-ounce scoop to drop mounds, leaving three inches between them. Dampen your fingers and pat down any peaks so they bake into perfect domes. Bake for 12 to 14 minutes until the edges are faintly golden and centers spring back—do not let the tops brown. Cool entirely on wire racks.
- 05
Whisk the confectioners' sugar, boiling water, corn syrup, and remaining vanilla into a glossy glaze.
It should be thick enough to coat the back of a spoon opaquely but fluid enough to level itself out. Transfer exactly half to a second bowl and vigorously whisk in the cocoa and espresso powder, adding a few drops of hot water if needed to return it to a spreadable consistency.
- 06
Frost the completely flat bottom of the cooled drop-cakes.
Always apply the white vanilla glaze first to one half of every cookie, drawing a sharp line directly down the center. Once the white side is done, apply the black chocolate glaze to the naked half, bringing it right up to the vanilla line for a seamless junction. Let them sit undisturbed for 30 minutes to set into a crackly crust.
Notes
Buttermilk can be easily hacked with whole milk and vinegar.
If you don't have buttermilk, combine one-third cup of whole milk with a teaspoon of white vinegar or lemon juice. Let it sit for five minutes to curdle—this provides the exact acidity needed to trigger the baking soda.
Proper storage preserves that fleeting deli freshness.
Because these are essentially cakes, they stale rapidly. Store fully set cookies in an airtight container at room temperature with wax or parchment paper between the layers, and eat them within two to three days.