Roughly break the cookies with your hands and place the broken pieces in a food processor, grind to a fine crumbs.
Place the cookies crumbs in a medium bowl and add the flour, cocoa powder, sugars and pecans.
Pour in the melted butter and use your fingers or a fork to incorporate all.
Preheat oven to 350F and line 2 8"x8" square pans with parchment paper, grease the sides.
In a medium bowl, sift the flour, baking powder and pumpkin spice, use a fork to stir and set aside.
Mix together the pumpkin puree and vanilla extract. Set aside.
In a bowl of a standing mixer, fitted with the paddle attachment mix the sugar and butter until incorporated. Slowly drizzle the oil and mix until light and fluffy.
Reduce speed to low, add eggs one at a time waiting for each egg to fully incorporate before adding the next. Scrap the sides and bottom of the bowl.
Add the flour mix in three additions alternating with the pumpkin puree. Once you added the last portion of the flour, stop the mixer and use a rubber spatula to incorporate any flour strikes.
Pour 1/4 of the batter into prepared pans, smooth it with a spatula and evenly sprinkle 1/4 of the streusels ontop. Repeat this step with the remaining batter and streusels.
Bake for 35-40 minutes or until toothpick comes out with a few moist crumbs from the center of the cake.
Allow to cool completely before slicing.