Preheat your oven to 350F and line a 12-cup muffin tin with parchment liners. In a small bowl, beat the cream cheese filling ingredients together until smooth, then scoop 12 small balls using a teaspoon and place them on a parchment-lined plate. Freeze for 15 minutes while you prepare everything else.
In a large bowl, whisk together the almond flour, granulated erythritol, baking powder, and salt.
Add the eggs, melted butter, sour cream, and vanilla extract to the dry ingredients. Stir until a thick, smooth batter forms with no lumps.
In a small bowl, stir together the melted butter, brown erythritol, and cinnamon for the swirl until well combined.
Spoon about 1 tablespoon of muffin batter into each liner. Place one frozen cream cheese ball on top of the batter in each cup, then divide the remaining batter evenly over the cream cheese balls.
Drizzle the cinnamon swirl mixture over the top of each muffin. Use a toothpick to gently swirl it into the batter in a figure-eight motion, keeping most of the swirl visible on top.
Bake for 22 to 25 minutes, until the tops are golden and a toothpick inserted near the edge comes out clean. Let the muffins cool in the tin for 10 minutes, then transfer to a wire rack.
While the muffins cool, whisk together the glaze ingredients until completely smooth. Drizzle generously over the warm muffins and serve.
