Add the milk to a small bowl. Add the vinegar and stir to combine. Let it sit for 5 minutes.
In a small bowl, combine the flour, brown sugar, baking powder, pumpkin pie spice, and salt.
In a larger bowl, combine the milk and vinegar, pumpkin puree, butter, eggs, and vanilla. Whisk until smooth.
Add the dry ingredients to the bowl of wet ingredients. Use a rubber spatula to combine everything together. Mix just until there are no large chunks of dry ingredients -- be careful to not overmix!
Add a bit of oil to a pan over medium heat. Add 1/3 cup of the batter to the pan. Cook for 2-3 minutes, then flip and cook for another 2-3 minutes. Repeat with the remaining batter.
While the pancakes cook, make the cinnamon butter. Add the butter, powdered sugar, honey, and cinnamon to a bowl. Use a hand mixer or stand mixer to whip the butter for 3-4 minutes until totally combined and slightly fluffy.
Add a scoop of butter on top of the pancakes. Add maple syrup or whatever you like! Enjoy!