Preheat the oven to 350 degrees. Place liners in your cupcake pans, set aside.
In the bowl of a stand mixer, cream together the softened butter and the granulated sugar until lighter in color and fluffy looking.
Add in the pumpkin spice, salt, baking powder, vanilla, milk, oil, pumpkin puree and egg whites. Mix again until well combined.
Lastly, add in the all purpose flour and mix very well. Stop the mixer and scrape down the sides when needed and mix again. Mixture should not contain any bumps or lumps.
Using an ice cream scoop or small measuring cup, scoop out enough batter to fill each cupcake cavity about ⅔-¾ full. The batter will rise slightly during bake time.
Bake in the preheated oven for 14-16 minutes or until set and edges are just slightly browned.
Allow to cool completely before attempting to remove from the pan.
To make the frosting: Mix together the softened butter and cream cheese in the bowl of a stand mixer. Add in the vanilla and salt. Finally add in the powdered sugar and mix until smooth. Mixture should be stiff peak consistency and creamy.
Transfer a few scoops of frosting to a pastry bag fitted with a large star tip and twist the end to keep the frosting contained. Gently pipe a dollop of frosting on each cupcake. Sprinkle with additional pumpkin spice to garnish.