Melt the mozzarella in a double boiler until smooth. Turn the heat off but keep the cheese warm to remain elastic.
Preheat a waffle maker/grill pan/sandwich grill for a few minutes.
In a medium-sized mixing bowl, combine the egg with the melted mozzarella cheese, Erythritol, peanut butter, vanilla extract, and a tiny pinch of sea salt. Mix well to make dough.
Add dollops of the batter to your waffle maker or grill pan/sandwich grill.
Cook for about 3-5 minutes, until the waffles are slightly golden around the edges.
Allow to cool for a few seconds, transfer on a cooling rack, and repeat with any remaining batter.
Serve with your favorite toppings.