Preheat the oven to 375° F. Line two half sheet baking pans with parchment paper. Set aside.

In a medium bowl add the all-purpose flour, cornstarch, baking soda, salt, cinnamon, ginger powder, freshly grated nutmeg and ground allspice. Whisk till combined, set aside.

In a large bowl combine the melted butter and brown sugar and whisk until fully incorporated. Add the egg, pumpkin puree, plain skyr and vanilla. Beat well. Fold the dry ingredients in until barely combined.

Stream in the milk and beat well with the mixer. Mix until a thick batter forms.

Depending on how big you want your whoopie pies, scoop the cookie dough in a small or large cookie scoop and release the batter onto the pan leaving plenty of space between each cookie.

Bake the cookies for 8-10 minutes or until the cookies have spread and no longer look wet in the center of the cookie. If the cookies look slightly wonky, adjust the warm cookies with a cookie cutter to round the edges.

In a large bowl, beat the room temperature butter along with the powdered sugar, spices and salt.

Once combined, scrape down the sides of the bowl with a spatula and add the skyr and vanilla extract.

Beat the buttercream with the skyr until smooth and thick, if it looks curdled add the heavy cream and continue to beat until the icing no longer looks split. Pipe the filling onto the bottom of a cooled pumpkin cookie and top it with another pumpkin cookie to create the whoopie pie. Repeat this process. Enjoy fresh! These also stay fresh up to 3 days sealed in an airtight container in the fridge.