Preheat the oven to 350 degrees F and grease an 8x8 baking dish with butter.
In a large, microwave-safe bowl, combine the mozzarella cheese, cream cheese, and butter. Microwave for 30-second intervals, stirring between each interval until the mixture is melted and smooth. Usually, about 2-3 minutes is needed.
Remove from the microwave and add the almond flour, coconut flour, sweetener, baking powder, and xanthan gum. Stir to combine, returning to the microwave if the cheeses start to harden.
Add the eggs and cornbread flavoring, then combine again. I found it easiest to use my hands for this part.
Once everything is mixed together well, transfer to the prepared baking dish and cover with aluminum foil. Bake for 30 minutes, then remove the foil and bake an additional 10-15 minutes or until the top is golden brown and the bread springs back when lightly pushed.
Allow to cool slightly before slicing and serving.