Using a few paper towels, pat the pumpkin puree dry. You may have to squeeze it, you want to get as much liquid out as possible.
Preheat oven to 350℉ and line a baking sheet with parchment paper.
In a large mixing bowl or the bowl of a stand mixer, combine melted butter and both sugars until smooth.
Add egg yolk, vanilla and squeezed pumpkin puree and mix until combined.
In a medium mixing bowl, whisk together flour, baking soda, salt, cinnamon and pumpkin pie spice.
Add dry ingredients to wet ingredients in two additions, mixing until combined before adding the next part. Mix just until you don't see any more floury bits.
Using a 1 tbs cookie scoop, scoop balls of dough onto your cookie sheet.
Bake for 8-9 minutes until the edges are just set. At 8 min, open the oven door, lift the pan up slightly and bang it on the rack twice. This releases any air and gives your cookies ripply edges.
Let them cool on the pan for 2 min then transfer to a cooling rack to cool completely.
Chop chocolate bar into small chunks and pour into a medium microwave safe bowl.
Add coconut oil and microwave in 30 second increments until melted and completely smooth. (mine took 30-60 seconds)
Dip the bottoms of each cooled cookie into the dark chocolate and let the excess drip off brushing the side of the cookie on the side of the bowl.
Place chocolate side down onto a baking sheet lined with parchment paper and repeat until baking sheet is full.
Place in the freezer for a few minutes to set up and the cookies should peel right off the paper.
Store in an air tight container in the fridge for up to one week. Enjoy!