Blot pumpkin puree with paper towels, pressing and replacing until it is darker, denser, and paper towels come away mostly dry. Measure 6 tbsp after blotting.
Mix cinnamon sugar coating in a small shallow bowl. Set aside.
In a medium bowl, whisk melted butter, both sugars, vanilla, and blotted pumpkin until smooth.
In a large bowl, whisk flour, salt, baking powder, baking soda, cinnamon, and pumpkin pie spice together.
Pour wet into dry and stir until just combined. Fold in white chocolate chips if using. Dough will be very soft.
Cover and refrigerate at least 30 minutes.
Preheat oven to 350 degrees Fahrenheit. Line baking sheets with parchment.
Scoop 1 and 1/2 tbsp portions, roll into balls, then roll each ball generously in cinnamon sugar coating. Place 3 inches apart on baking sheets. Slightly flatten each with the back of a spoon.
Bake 11 to 12 minutes until edges are set. Centers will look soft — correct.
Cool on baking sheet 10 minutes. Transfer to wire rack and cool completely. Best on day two.