1. Preheat the oven to 350 degrees Fahrenheit and line two baking sheets with parchment paper.
2. In a large bowl, whisk the flour, salt, baking powder, baking soda, cinnamon, ginger and all-spice together and set aside.
3. In a separate bowl, whisk the brown sugar and oil together until well combined. Add the pumpkin puree and orange zest and whisk to combine thoroughly. Add the eggs and vanilla paste and mix until combined.
4. Sprinkle the flour mixture over the pumpkin mixture and whisk until all the ingredients are well combined.
5. Using a small ice cream scoop with a release mechanism, drop the dough onto the prepared baking sheets at about one-inch apart.
6. (Optional) Alternatively, you can use a medium size ice cream scoop or a piping bag and pipe round mounds of batter that are about 1-ounce in volume.
7. Place the baking sheets in the preheated oven and bake for 15 to 17 minutes or until a toothpick inserted into the center of the cookie comes out clean. Remove from the oven and allow the cookies to cool completely on a cooling rack while you make the filling.

For the Cream Cheese Filling:

1. In a medium mixing bowl, sift the confectioners' sugar and set aside.
2. In the bowl of an electric mixer fitted with the paddle attachment, beat the butter until it's completely smooth. Add the cream cheese and beat until the mixture is smooth and well combined.
3. Add the confectioners' sugar and the vanilla paste and beat until smooth. Don't over beat the filling or it may separate.

Assemble:

1. Turn half of the cooled cookies upside down (flat side facing up).Use an ice cream scoop or a tablespoon to drop a large dollop of filling onto the flat side of the cookie. Place another cookie, flat side down, on top of the filling. Press down slightly so that the filling spreads to the edges of the cookie. Repeat until all the cookies are used. Put the whoopie pies in the refrigerator for about 30 minutes to firm up before serving.