Preheat your oven to 350 degrees. Line baking sheets with parchment paper and set aside
In a large bowl mix together the flour, baking soda, salt, cinnamon, nutmeg, cloves, and all spice. Set aside.
Mix together the melted butter, brown sugar, and granulated sugar until smooth, about one minute. Add in the egg yolk, then the vanilla, then the pumpkin, mixing a little until after adding each ingredient. Mix until well combined, about 30 seconds.
Add in the flour mixture. Mix on low for less than a minute, just until the flour will not fly out of the bowl. Turn the mixer up, and mix for just a few seconds - just until the flour is fully integrated and no streaks remain.
Stir in the milk chocolate chips.
Form into 1 1/2 tablespoon dough balls. Place 2 inches apart on the prepared baking sheets. Bake for 10 to 12 minutes, rotating the pans half way through, until the edges just begin to brown. Be careful not to over bake.
Let sit on the baking pan two minutes, then remove to a cooling rack and allow to cool completely.