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 combined.
04 - Add the melted cheese mixture and eggs to the dry ingredients. Mix with a spatula until a sticky dough forms. Lightly oil hands to handle dough more easily.
05 - Place 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. Spread evenly over the rolled dough surface.
07 - Using the parchment paper for support, gently roll the dough into a tight log from the long edge. Slice into 8 equal pieces.
08 - Arrange buns cut-side up in prepared baking pan. Bake for 22-25 minutes until golden brown and set in center.
09 - While buns bake, beat softened cream cheese, butter, powdered erythritol, and vanilla until smooth. Add almond milk 1 tablespoon at a time to achieve spreadable consistency.
10 - Remove buns from oven and let cool for 10 minutes. Spread icing generously over warm buns before serving.