Add the butter and brown sugar to a medium bowl. Mix together with an electric mixer on high speed until combined.

Add in the flour, pumpkin pie spice and salt and mix together until the mixture resembles large crumbs. (You may need to use your hands for this part.)

Pop the streusel in the fridge to chill while making the pumpkin cookie dough.

Preheat the oven to 350°F. 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 (122 g) dried down to just about a ¼ cup (~42 g). 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.

In a small bowl, whisk together the flour, pumpkin pie spice, baking soda, baking powder and salt. Set aside.

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.(You can also use the bowl of a stand mixer fit with a paddle attachment.)

Add in the egg yolks and vanilla and mix on medium speed until pale and fluffy, about 1-2 minutes.

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. (If the dough is too "sticky" chill it in the fridge for 10 minutes, then proceed.)

Scoop the dough with a 2 tablespoon cookie scoop and roll into balls.Transfer the cookie dough, six at a time, to a prepared baking sheet.Make a slight indent in the cookie dough balls using the palm of your hand. Measure out a slightly packed, heaping tbsp of streusel topping and flip it on top of each portion of cookie dough. Press down gently with the palm of your hand to better secure the streusel to the cookie dough.

Bake the cookies for 11-12 minutes. When the cookies are straight out of the oven, scoot a large, round cookie cutter around them to give them a perfect circular shape. Let them cool for 10 minutes on the cookie sheet, then transfer the baked cookies to a wire rack to cool completely.

While the cookies cool make the vanilla glaze by mixing the powdered sugar, vanilla extract and milk together in a small bowl until you achieve a drizzle-able consistency. (Start with 2 tsp of milk and add more as necessary.)

Once the cookies are cool, drizzle the vanilla glaze over them and serve!