01 - Preheat oven to 350°F. Line an 8-inch round baking pan with parchment paper or lightly grease with butter.
02 - Combine shredded mozzarella and cream cheese in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until completely melted and smooth.
03 - In a large mixing bowl, whisk together almond flour, coconut flour, erythritol, baking powder, and salt until well incorporated.
04 - Add the melted cheese mixture and eggs to the dry ingredients. Mix thoroughly with a spatula until a uniform dough forms. Lightly oil your hands if the dough feels too sticky.
05 - Place the dough between two sheets of parchment paper. Roll into a rectangle approximately 1/4-inch thick.
06 - Mix erythritol, ground cinnamon, and melted butter in a small bowl until combined.
07 - Spread the cinnamon filling evenly over the rolled dough. Using the parchment paper for assistance, roll the dough into a tight log from the long edge.
08 - Cut the log into 8 equal pieces. Place the buns cut-side up in the prepared baking pan.
09 - Bake for 22 to 25 minutes until golden brown and set in the center.
10 - While buns bake, beat softened cream cheese, butter, powdered erythritol, and vanilla extract until smooth. Add almond milk 1 tablespoon at a time until spreadable consistency is achieved.
11 - Remove buns from oven and let cool for 10 minutes. Spread icing generously over warm buns before serving.