1. Blot pumpkin puree with a paper towel to remove excess moisture.
2. In a bowl, cream butter, brown sugar, and granulated sugar until pale and fluffy.
3. Mix in blotted pumpkin puree and vanilla until combined.
4. In another bowl, whisk flour, salt, pumpkin pie spice, and baking soda.
5. Fold dry ingredients into wet mixture until just combined.
6. Fold in white chocolate chips. If dough is sticky, add 1 tablespoon flour at a time.
7. Cover and refrigerate for at least 2 hours or overnight.
8. Preheat oven to 380°F.
9. Scoop dough into balls, place 2 inches apart on a parchment-lined baking sheet, and flatten slightly.
10. Bake for 10-11 minutes until edges are golden.
11. Let cookies rest on the sheet for 5 minutes, then transfer to a rack.