Whisk together all purpose flour, cocoa powder, sugar, and salt. Using a pastry cutter or two forks, cut the vegan butter until the mixture in crumbly and the butter is about pea-sized. Add in the ice cold water tablespoon by tablespoon until the dough forms. It shouldn't be too sticky or wet. 

Lightly flour a clean surface. Roll the dough out and form in to a ball. Cut the ball in half. Wrap both in plastic wrap. Refrigerate for 1 hour. 

While the dough is chilling, make the fudge filling. Melt the vegan butter and chocolate chips on low heat in a saucepan. Add the cocoa powder, brown sugar, non-dairy milk, and pinch of salt. Whisk until completely combined and smooth. Transfer fudge sauce to a bowl and place in fridge until ready to use. The fudge will thicken as it cools.

After 1 hour, pull half of the dough out of the fridge. Leave the other half in the fridge so it stays cold. Lightly flour a large piece of parchment. Roll the dough into a rectangle about ⅛ inch thick. Trim the edges and cut out 8 rectangles. 

Pour the aquafaba from the chickpeas in to a small bowl. Set aside the chickpeas for another recipe. Lightly brush each rectangle with aquafaba and then place 1 heaping tablespoon of the cooled fudge mixture in the center of 4 out of the 8 rectangles. Leaving the edges clean. Carefully place the other side of the dough on top of the fudge and press the edges of the pop tart together, sealing in the fudge. Seal the edges by crimping with a fork, to prevent the sides from opening as the pop-tarts bake. 

Set these 4 pop tarts on a baking tray and place in freezer. Continue to roll out the other half of the day the same way to make 4 more pop tarts. Place finished pop tarts on same baking tray. Freeze for 15 minutes. 

While the pop tarts are in the freezer, preheat oven to 400F. Pull pop tarts out of the oven and lightly brush with aquafaba. *Do not discard the remaining aquafaba or remaining fudge filling. We will be using both in the next step.* 

Bake for 22-25 minutes or until pop tarts are firm. 

Let cool completely. Once pop tarts are cooled, make marshmallow meringue. In a stand mixer, add the aqaufaba and cream of tartar. Beat on high until stiff peaks have formed. Now, slowly sprinkle in the powdered sugar. Do this very slowly or the meringue will deflate. Once all the sugar has been added, turn off the mixer. 

Carefully spread a good amount of the meringue on top of each pop tart. Set your oven to broil. Broil the meringue topped pop tarts for a few minutes or until the top starts to turn lightly golden. Keep an eye on them. This won't take long. Now, add a tablespoon or 2 of hot water to the remaining fudge mixture to thin it out. Drizzle the remaining fudge over the pop tarts.