In a large bowl, mix the peanut butter and egg until well combined with a spoon. Slowly stir in the marshmallow cream until just combined. You want to see the marshmallow cream not fully incorporated, almost like swirled through. With a small-medium cookie scoop, scoop dough onto a parchment or silpat lined baking sheet. Bake for 12-15 minutes or until baked through. Let cool for 5 minutes on cookie sheet before transferring to a cooling rack. Definitely grab some milk with these bad boys and enjoy!