In a small bowl, stir together the melted butter, brown sugar, and cinnamon until smooth. Spoon the mixture into a zip top bag and set it aside.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
In a second bowl, whisk the buttermilk, eggs, melted butter, and vanilla until smooth.
Pour the wet ingredients into the dry ingredients and gently stir until just combined. A few lumps are perfectly fine.
Heat a nonstick skillet or griddle over medium heat and lightly grease it.
Pour about one quarter cup of batter onto the hot pan. Snip a small corner off the cinnamon bag and pipe a spiral on top of the pancake.
Cook until bubbles form and the edges look set, then gently flip and cook for another one to two minutes.
While the pancakes cook, beat the cream cheese, powdered sugar, milk, and vanilla until smooth.
Stack the warm pancakes on a plate and drizzle generously with glaze.