Melt the butter and set aside to cool slightly.
Blot out some of the excess moisture in the pumpkin using paper towels. You don't have to get all of the moisture since we still want the pumpkin flavor in the cookies. Measure out 1/3 cup pumpkin AFTER moisture is removed.
In a medium sized bowl, whisk together the melted butter, brown sugar, white sugar, pumpkin, egg and vanilla extract.
1/2 cup melted butter, unsalted and slightly cooled, 1/2 cup brown sugar, packed, 1/4 cup white granulated sugar, 1/3 cup 100% pumpkin puree, blotted* (see notes), 1 large egg, whisked, 1 tsp. vanilla extract
In a large bowl, whisk together the dry ingredients. Fold the dry ingredients into the wet ingredients. (It might not look like it's incorporating at first but keep folding, it will all come together I promise!)
1 cup All-Purpose Flour, 1 cup Cake flour, 1 tsp. corn starch, 1 tsp. cinnamon, 1 tsp. pumpkin pie spice, 1/2 tsp. baking soda, 1/2 tsp. baking powder, 1/2 tsp. salt, 1/4 tsp. cream of tartar (optional for snickerdoodle taste)
Fold in white chocolate chips. Chill cookie dough batter for at least 30 minutes. You can scoop the cookie dough into balls first if you'd like, then refrigerate so it's easier to work with.
1 cup white chocolate chips
Preheat the oven to 400°F.
Line 2 baking sheets with parchment paper or silicone baking mats.
Mix together the sugar and cinnamon for rolling and roll each cookie dough ball in the cinnamon-sugar mixture.
2 Tbsp. white granulated sugar, 1 tsp. cinnamon (or pumpkin pie spice)
Arrange the cookies on prepared baking sheets, and slightly press down just a little. (see video)
Bake for 9-10 minutes or until edges appear set. May take a minute or two longer, ovens vary. Cookies will look and feel very soft when you take them out. Top with more white chocolate chips when they come out of the oven, if desired.
Let them rest on the cookie sheet for 15 minutes, then transfer to a cooling rack. (I find they are best and most chewy at least an hour later, and even so soft the next day!). Enjoy!