Preheat and prep: Set your oven to 350°F (175°C). Line an 8- or 9-inch round cake pan with parchment or lightly grease it. Have two sheets of parchment ready for rolling the dough.
Make the filling: In a small bowl, mix the softened butter, sweetener, cinnamon, and a pinch of salt until smooth.
Set aside; it should be spreadable.
Melt the cheese: In a medium saucepan over low heat (or a microwave-safe bowl), add mozzarella and cream cheese. Warm gently, stirring often, until fully melted and stretchy. Avoid overheating—just melt until combined.
Mix dry ingredients: In a separate bowl, whisk almond flour, baking powder, granulated sweetener, and salt.
Form the dough: Add the dry mixture, egg, and vanilla to the warm cheese.
Stir with a stiff spatula until a shaggy dough forms. Knead with clean, lightly oiled hands for 30–60 seconds until smooth and cohesive.
Roll it out: Place the dough between two sheets of parchment. Roll into a rectangle about 10x14 inches (25x35 cm).
If it resists, warm it for 10–15 seconds and continue.
Add the filling: Peel off the top parchment. Spread the cinnamon butter evenly, leaving a 1/2-inch border on one long edge to seal.
Roll and slice: Starting from the opposite long edge, roll into a tight log, using the parchment to help. Pinch the seam closed.
Use a sharp knife or unflavored dental floss to slice into 9 even rolls.
Arrange in the pan: Place the rolls cut-side up in the prepared pan with slight space between them. If they look uneven, nudge them into rounder shapes.
Bake: Bake for 18–24 minutes, until lightly golden on top and set in the center. Do not overbake—fathead dough can dry quickly.
Make the glaze: While they bake, beat cream cheese, butter, powdered sweetener, vanilla, and salt until smooth.
Add heavy cream 1 tablespoon at a time until pourable but thick.
Glaze and serve: Cool the rolls for 10 minutes, then spread or drizzle the glaze over warm rolls so it melts slightly into the swirls. Serve warm.