- Melt your butter in the microwave for about 40 seconds (it won’t be fully melted). Then let it chill for about 20 minutes so its no longer hot.  
- Cream together the butter and sugars for about two minutes till light and creamy. 
- Add in the egg yolk, vanilla, and pumpkin purée. Stir till just combined. 
- Stir in the baking soda, salt,  flour, cinnamon, and pumpkin pie spice. 
- Fold in the white chocolate chips. 
- Cover the dough and refrigerate for one hour, up to overnight. 
- Preheat the oven to 350 degrees. 
- Scoop the cookie dough into 2-2.5TBS sized balls. Roll into balls and place on a lined cookie sheet. 
- Slightly flatten each cookie dough ball. 
- Place pan into the oven and bake for 12-14 minutes, until cookies look set in the edges and mostly set in the middle. 
- Allow cookies to rest on the cookie sheet for another 3 to 4 minutes as they continue cooking on the pan. 
- Place a few extra white chocolate chips on the top of each cookie for looks, if desired. 
- Remove from pan to a cooling rack and cool completely.