Place a cheesecloth or paper towel into a fine mesh sieve and add the pumpkin. Firmly blot the pumpkin with a paper towel to remove excess moisture. Repeat as needed until very dry.
In a medium-sized bowl, whisk together the flour, pumpkin pie spice, baking powder, baking soda, and salt.
In a large bowl or stand mixer, cream the butter and sugar together until fluffy, about 3-4 minutes.
Add the egg yolks and vanilla and continue beating until smooth.
Add the dried pumpkin and beat until just combined.
Add the flour mixture slowly and mix with a spatula until just combined.
Stir in the chocolate chunks.
Roll the dough into 2-inch balls and place them onto a cookie sheet about 3 inches apart.
Press the balls into flat discs.
Bake for 14-15 minutes, until puffy but matte and set. Cool on the baking sheet for 8-10 minutes.
Remove and let the cookies cool completely on a wire rack before serving.