Preheat the oven to 375°F.
Line a baking sheet with parchment paper (or spray a whoopie pie pan with non-stick spray)
In a bowl, beat the butter, oil, sugar, molasses, baking powder, baking soda, salt, and spices together on medium speed until completely combined and smooth.
Scrape down the sides of the bowl and add the eggs in one at a time and continue beating until combined.
Reduce the speed to low and beat in the pumpkin.
Add half of the flour and beat on low until combined. Add remaining flour and beat until combined
Use a medium cookie scoop (1 ½ T size) to drop the batter on the prepared cookie sheet OR fill each cavity of a whoopie pie pan ½ full.
Bake about 10 - 12 minutes until the cookies are firm on top and lightly browned on the edges.
Remove from oven and let sit in the pan for a few minutes before transferring to a colling rack to cool completely before filling