• Preheat oven to 350°F (180°C) and line an 8x8" pan with parchment paper. Arrange the graham crackers in a neat layer at the bottom of the pan. Set aside.
• In a tiny bowl, combine the flaxseed with 3 tbsp of water and set aside to thicken. After about 5 minutes, the mixture should have a thicker almost gel like consistency similar to an egg. (Disregard this step if using an egg)
• In a large bowl, sift the cocoa powder, cornstarch, baking soda, coco sugar and salt. Mix until combined. Proceed to pour in the flax egg, agave, milk, and vanilla.
• Stir in the peanut butter until fully incorporated into the batter (I recommend using a wooden spoon for this). No need to worry about over mixing here as there is no flour. Stir in the chocolate chunks.
• Ceremoniously dump brownie batter on to the graham-lined pan and evenly spread using a rubber spatula. Bake in the oven for 15 minutes or until the center appears firm but still is soft. Let cool.

Marshmallow Fluff

• In the bowl of your stand mixer fitted with the whisk attachment, whip the aquafaba and cream of tartar for 6 minutes or until very fluffy. Pause, add the vanilla and beat for another 3 minutes to form stiff peaks.
• While the whipping is ongoing, place water and agar agar in a heavy bottomed pot (if you have a candy thermometer attach it now) and place over low heat, slowly bring to a boil. Boil for 3 minutes while stirring continuously. Gently add the sugar and boil for an additional 3 minutes or until it reaches 235°F on your thermometer.
• With the mixer speed on low, drizzle the sugar syrup into the aquafaba and beat for 5 minutes until it develops a slight sheen.
• Top your brownies with the marshmallow fluff then use a torch to toast the marshmallow. Alternatively, set your oven to broiler and toast until tops have browned, 1-2 minutes.