Preheat oven to 350°F. Line 3 large cookie sheets with parchment paper.
In a large bowl, cream the butter, brown sugar, and granulated sugar with an electric mixer until light and fluffy. Mix in the pumpkin puree, vanilla extract, and yolks until combined.
Mix in the pumpkin pie spice, baking soda, baking powder, and salt, then add about half of the flour and mix before adding the remaining flour. Continue mixing until the dough is thick. Fold in the white chocolate chips.
Use a medium cookie scoop (1 ½ tablespoons) to scoop out the dough and drop it on the parchment-lined cookie sheets. Press a few extra white chocolate chips into the tops of the cookies.
Bake the cookies, one batch at a time, for 12 minutes or until the cookies look set around the edges and look puffy in the middle. Let the cookies cool on the cookie sheet for 15 minutes before transferring them to a wire rack to cool completely.
Serve warm or at room temperature.