Whisk together the dry ingredients in a large bowl: flour, brown sugar, baking powder, baking soda, salt, pumpkin pie spice, and cinnamon.
In a small bowl, mix together the pumpkin puree, buttermilk, melted and cooled butter, eggs, and vanilla.
Add the wet ingredients to the dry ingredients and mix until just combined. Be careful not to overmix.
Make the cinnamon butter by beating together the butter, powdered sugar, cinnamon, vanilla extract, and salt using an electric mixer. Set aside.
In a pan over medium heat, add a little butter or cooking oil.
Use a ladle or large spoon to scoop out dollops of pancake batter, about 1/4 a cup of batter. Cook for 2-3 minutes on each side or until you see bubbles start to form.
Top your pancakes with a dollop of the cinnamon butter, maple syrup, and a sprinkle of pumpkin pie spice if desired.