The key to light and fluffy vegan black and white cookies appears to be substituting in aquafaba (the juice from a can of chickpeas) in place of an egg in a standard recipe. I've made other versions and with the traditional egg replacers like Ener-G or flax seeds, you can often taste the replacement. Here you do not; it's pure vanilla cookie flavor.
Black and white cookies are so nostalgic to New York City for me. It is, after all, where they got their start, and where you can find them in every bakery. Normally they're huge, bigger than the palm of your hand. And they're always cakey, more a small cake than a big cookie, as there's no crunch to them.
Preheat the oven to 350 degrees Fahrenheit. Prepare a cookie sheet with either parchment paper or silpat liners and set aside.
Combine the nondairy milk and the apple cider vinegar and set aside for 5 minutes.
In a large bowl combine the flour, baking soda, and salt and stir well.
Cream the butter and sugar and then add in the aquafaba and vanilla. Gradually add in the dry ingredients so they don't fly out of the mixing bowl. (Note: I've forgotten to cream the butter and sugar before and just ended up smashing the butter into the batter by hand and it ended up just fine. Technically you should cream it though.)
Spoon the cookie batter in 1/4 cup dollops onto the prepared cookie sheet.
Bake for 15 minutes, or until the edges are golden brown and the top is springy. You will have little mound-shaped cookies with a cakey middle.
Allow the cookies to cool completely on a cooling rack before frosting them.
Combine the sugar, agave nectar, lemon juice, vanilla, and half the water until smooth and silky. Add more water if the frosting doesn't look spreadable, but go slowly so you don't have a runny frosting.
Pour half the vanilla frosting into a second bowl and add in the cocoa powder. Stir and add more water by the tablespoon until it's the same consistency as the vanilla frosting.
Flip the cookies over and frost half the bottom of the cookie with the white frosting, and then let it rest on the cookie sheet, frosting side up. Once you've frosted all the white, do the other side in the black frosting.
I got festive for Halloween with this batch of vegan black and white cookies and made spider webs and a spider by just adding my leftover frosting into plastic bags and snipping the tiniest hole in the corner to decorate.
Enjoy these classic New York City-style cookies!