This giant black and white cookie is a huge version of the classic New York treat!
Ingredients
Cookie Cake:
166g (~1¼ cups) all-purpose flour
145g (~1¼ cups) cake flour
1g (1/4 teaspoon) baking powder
1g (1/4 teaspoon) salt
113g (1/2 cup / 1 stick) unsalted butter, softened at room temperature
175g (~3/4 cup + 2 tablespoons) granulated sugar
1g (~1 teaspoon) lemon zest
105g (2 large) whole eggs, at room temperature
177 milliliters (3/4 cup) milk at room temperature
2 milliliters (1/2 teaspoon) vanilla extract
Icing:
320g (~2 cups) powdered sugar
45-60 milliliters (3 tablespoons – ¼ cup) cup boiled water
43g unsweetened chocolate, roughly chopped
1 teaspoon light corn syrup
Instructions
Pre-heat oven to 375 degrees; line a baking sheet with parchment paper and set aside
In the large bowl of an electric mixer, cream butter, sugar and lemon zest on high speed until light and fluffy
In a medium bowl, whisk together flours, baking powder and salt; set aside
Reduce speed to medium and add eggs, one at a time; add milk and vanilla; mix on medium speed until combined and then scrape the sides of the bowl with a spatula
Add half of dry ingredients and mix on low speed just until combined; add remaining dry ingredients and mix on low just until combined; do not overmix
Use your spatula spread dough into a large round cookie shape (10 inches in diameter)
Bake for ~20 minutes or until edges are golden brown and a toothpick comes out clean from center
Cool cake completely before making icing
To make icing, place powdered sugar in a large heat-safe bowl
Whisk in about ¼ cup of boiling water; continue to whisk and add water, about one tablespoon at a time, until you have a thick but spreadable mixture; be careful not too add too much water or icing will be too runny
Carefully turn cookie cake upside down (you will want flat side on top)
Spread icing over half of cookie
Place remaining icing over a pot of simmering water and whisk in unsweetened chocolate until melted; stir in light corn syrup and remove from heat
Ice the “naked” half of the cookie with chocolate frosting; if the frosting becomes to dry to spread, whisk in an additional teaspoon of hot water as needed, again careful not to make icing too runny
Allow icing to set before serving
Cookie cake is best enjoyed the day it is made but leftovers can be stored in an airtight container or ziplock bag up to three days