In a small bowl, mix vegan butter, brown sugar, cinnamon, and 3 tbsp of pancake batter until smooth. Transfer to a zip-top bag or piping bag and snip a tiny corner. Set aside.
In a medium bowl, whisk together flour, baking powder, and sugar. Add melted butter, oat milk, and vanilla. Mix gently until just combined; a few lumps are fine.
Heat a non-stick skillet over medium heat and lightly grease with vegan butter or oil.
Pour 1/4 cup of the pancake batter into the skillet. Pipe cinnamon filling swirls on top of each pancake.
Cook 2–3 minutes, until bubbles form and edges start to set. Flip carefully and cook another 2–3 minutes.
While pancakes cook, mix cream cheese, maple syrup, and oat milk until smooth.
Drizzle glaze over warm pancakes and serve immediately.