Preheat oven to 350 degrees and line two baking sheets with parchment paper.
Start by drying your pumpkin. (This step is not optional. The cookies will not bake properly if you skip this step.) Spread the canned pumpkin on a plate and lightly press with a paper towel to absorb the excess liquid. Repeat the step at least four more times. The pumpkin should be dry enough that it goes from being ½ cup dried down to just about a ¼ cup. Hardly any liquid should transfer onto a paper towel once it has been dried enough.(Like stated above, try to use Libby's canned pumpkin as almost all cans of it have the same consistency and are not too wet.) Then set aside. ½ cup (122 g) canned pumpkin puree
In a small bowl, whisk together the flour, pumpkin pie spice, baking soda, baking powder and salt. Set aside.
1 ¾ cups (219 g) all purpose flour, spooned and leveled, 1 tablespoon pumpkin pie spice, ½ teaspoon baking soda, ½ teaspoon baking powder, ½ teaspoon salt
In a large bowl cream the softened butter and brown sugar together with an electric mixer on high speed for 1-2 minutes until light and fluffy.
¾ cup (168 g) unsalted butter, softened, 1 cup (220 g) light brown sugar, packed
Add in the egg yolks and vanilla and mix on medium speed until pale and fluffy, about 1-2 minutes.
2 egg yolks, at room temperature, 2 teaspoon vanilla
Add in the pumpkin and mix on medium-low speed to combine.
Add in the dry ingredients and mix on low speed just until combined.
Scoop the dough with a 2 tablespoon cookie scoop, and roll them into balls. Then roll the dough balls in the spiced sugar. (If the dough is too "sticky" chill it in the fridge for 10 minutes, then proceed.) Place the cookie dough balls at least 2 inches apart on the baking sheets. (I usually bake 6 at a time.)
Bake the cookies for 12-14 minutes. (12 minutes for really chewy centers, 14 minutes for a slightly crispier cookie). When the cookies are done baking the centers will be puffy. As they cool the centers will fall and the cookie will get "wrinkly".
Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a cooling rack to finish cooling. They are best enjoyed when they have cooled for at least 15 minutes!