Preheat the oven to 375 F and line a baking sheet with parchment paper. In a microwave-safe bowl melt the mozzarella and cream cheese together in 30 second bursts, stirring until smooth and stretchy.
In a separate bowl whisk the almond flour, coconut flour, baking powder, salt, and garlic powder. Add the melted cheese mixture, whole egg, and egg yolk. Knead until a soft, uniform dough forms.
Divide the dough into 8 equal pieces and roll each into a smooth ball. Place them on the baking sheet with a little space between each roll.
Brush the tops with melted butter. Bake for 18 to 22 minutes until puffed and golden brown.
Brush once more with remaining melted butter right out of the oven. Cool for 5 to 10 minutes so the centers set soft and fluffy.