Preheat the oven to 350°F
Combine the vinegar with the plant milk & then add the vanilla & the butter flavor
In a small bowl combine the aquafaba with the cornstarch & whisk smooth
Cream the slightly softened but still cold vegan butter with the sugar with an electric mixer on medium to high speed until light & fluffy this will take about 4 minutes
Stop the mixer to scrape the bottom & sides of the bowl then resume mixing on medium speed & slowly add the aquafaba mixture while mixing.
Once it is all incorporated whip on high speed for about 20 seconds to emulsify
Add the flour, baking powder & soda & salt & mix until it comes together to a firm dough
Add the milk mixture slowly while mixing on medium speed, then scrape the bottom & sides of the bowl again & whip smooth for 20 seconds
Pipe the batter with a pastry bag to 3" in diameter or scoop with a 2 ounce scoop *this is for the large size onto a parchment lined sheet pan spaced 2" apartFor the mini size cookies use a tablespoon scooper or pipe to 1½" diameter*recipe makes 18 Lg or 48 Mini Tap the sheet pan firmly on the table to release any air pockets
Bake in the preheated 350°F oven for 15 minutes or until golden brownThe mini size will take just about 10 minutes While the cookies are cooling prepare the icing by mixing the confectioners sugar with the plant milk & corn syrup until it is a thick glossy icing *it is much easier to do this with an electric mixer
Divide the icing in half then combine the cocoa powder with the hot water (you may only need 4 tablespoons so add a little at a time) to form a thick paste
Add the cocoa paste to the half of the icing sugar then ice the cookies half with white icing & then the other half with chocolate icing as shown in the video