Mix first 6 ingredients together until smooth. The vegan butter will melt on its own just by the shear power of your mixing ;)
Next add in the rest of the ingredients until everything is fully incorporated. I had a couple of marshmallow pieces leftover, so I reserved them for topping.
Spoon onto a parchment paper lined tray. The batter will be sticky, so it's best to use the "drop method" of using a tablespoon to scoop the batter then drop it onto the paper. Press in the extra marshmallows and/or extra chocolate chips and refrigerate overnight or until firm!
Store these no-bake cookies in the fridge!