Makes: 3 to 4 dozen
Time: About 30 minutes, plus time to frost
This is a New York City classic, a thing I grew up with, now usually—and sadly—sold wrapped in plastic. Making them at home ensures freshness—the cakelike cookie stales faster than most—and undoubtedly better ingredients.
1.Heat the oven to 375°F. Whisk together the flour, cornstarch, baking powder, and salt in a medium bowl and set aside.
2. Cream the butter and sugar in a large bowl until light and fluffy. Beat in the eggs, then add the milk and vanilla. With a rubber spatula, fold in the flour mixture, about 1 cup at a time, mixing until just incorporated with each addition. Add the lemon zest with the last of the flour.
3. Drop about 2 tablespoons of the dough in mounds onto lightly greased baking sheets about 3 inches apart; use the spoon to spread them a bit into nice circles. Bake for 15 to 20 minutes, until the edges are golden. Cool for about 2 minutes on the sheets, then transfer the cookies to wire racks to cool completely.
4. While the cookies bake, make the glaze. Reserve half of the glaze; stir the cocoa into the remaining glaze until fully incorporated. Add water as needed, 1 teaspoon at a time, to thin the chocolate glaze.
5. Flip the cookies upside down (so that you’re glazing the flat side) and coat half in a thin layer of the white glaze. Coat the other half in chocolate glaze and let set at room temperature. These will keep in an airtight container, between sheets of waxed paper, for no more than a day or two.