In a small bowl, mix together the brown sugar and ground cinnamon. Add the softened butter and mix until it forms a paste. Set aside.

In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt until well combined.

In a separate bowl, combine the buttermilk, beaten egg, and melted butter. Whisk until smooth.

Pour the wet ingredients into the dry ingredients and gently mix until just combined. Be careful not to overmix; a few lumps are okay.

Preheat a non-stick skillet or griddle over medium heat. Lightly grease with cooking spray or a small amount of butter.

Pour about 1/4 cup of pancake batter onto the skillet. Using a piping bag or a zip-top bag with the corner snipped off, pipe a swirl of the cinnamon filling on top of the pancake batter.

Cook until bubbles form on the surface of the pancake and the edges look set, about 2-3 minutes. Carefully flip the pancake and cook for an additional 2-3 minutes until golden brown.

Repeat with the remaining batter and filling, adjusting the heat as necessary to prevent burning.

In a mixing bowl, beat the softened cream cheese until smooth. Gradually add the powdered sugar, mixing until well combined.

Add the milk and vanilla extract, and mix until the glaze is smooth and pourable. Adjust the consistency with more milk if necessary.

Stack the pancakes on a plate and drizzle generously with the cream cheese glaze. Serve warm and enjoy!