Preheat oven to 350F. Line a muffin tin with cupcake liners and set aside.
In a large bowl, whisk together the pumpkin, oil, milk, eggs, brown sugar and white sugar. Add flour, baking powder, baking soda, pumpkin pie spice, cinnamon and salt, and fold together with a spatula until no dry patches remain.
Scoop batter into muffin tin, filling wells about ⅔ full.
Bake for 22-27 minutes. Allow to cool in the pan for about 5 minutes before removing to a cooling rack.
In a small bowl, stir together cinnamon and sugar.
Once muffins have cooled a bit, brush with a bit of melted butter and dip in the cinnamon sugar mixture.
