Line a baking sheet with parchment paper. Preheat the oven to 350 degrees.
You must put the pumpkin puree in a paper towel and squeeze out the excess liquid. This helps the cookies from becoming cakey in texture.
Melt the butter over medium heat in a saucepan. Stir every minute until the butter has browned.
Pour the browned butter into a mixing bowl and add the brown sugar. Whisk.
Add the vanilla and egg yolks. Blend with a whisk. Add the pumpkin puree and mix.
Add the pumpkin pie spice, flour, baking soda, and salt. Use a mixer to mix together to form the cookie dough.
Fold in the chocolate chunks, but leave out a few to add to the tops of the cookies.
Make cookie dough balls using a 1-2 inch scooper. Place them on the baking sheet. Cover them with plastic and put the sheet in the fridge for 30 minutes. (leave about 2 inches between each cookie dough ball)
Add a few chocolate chunks to the top of each ball of dough.
Put the cookies in the oven and bake for 12-13 minutes or until the cookie edges are browned slightly.
Let the cookies cool for 10 minutes, then move to a cooling rack.