Preheat the oven to 350°F
Cream the room temperature vegan butter & sugar on medium to high speed until light & fluffy about 5 minutes.
Be sure to scrape the bottom & sides of the bowl from time to time to ensure an even mix.
Combine flax meal with the warm aquafaba & let stand for 5 minutes to thicken to a paste. Add the vanilla extract
Add the flax paste to the creamed butter/sugar & then whip on high speed for about 10 seconds to emulsify
Sift the flour with the salt, baking powder & cocoa powder then add it all at once to the creamed mixture. Blend on low to incorporate all the flour
Now mix on high speed for about 5 seconds to develop the dough.
With your with the #826 Ateco tip or with a cookie press pipe the dough onto a parchment lined sheet pan spaced about 1 inch apart.
Bake in a preheated 350°F for about 18-20 minutes ** See notes above! or until the cookies are medium browned on the edges
Cool completely and fill with jams, vegan chocolates, or your choice of fillings and then dip in nuts and/or sprinkles of your choice.