In a bowl whisk together all purpose flour, salt, baking soda and pumpkin pie spice. Set aside.
Using the steel bowl of your stand mixer fitted with paddle attachment or using your hand mixer, beat cream butter till smooth and creamy.
Add brown sugar and cream butter and sugar together till smooth.
Add egg, vanilla extract and pumpkin puree and mix till combined.
Add the flour mix to the wet ingredients and mix till combined.
Cover the cookie dough and chill in the refrigerator for 2 hours. Because the dough is little sticky, it's easier to work with it when it's chilled.
Once the dough has chilled, line 2 baking sheets with parchment paper. Take 1/8 cup (around 2 tablespoons) of dough per cookie.
Because I wanted flatter cookies, I pressed each with the back of a measuring cup. This step is optional.
Bake the cookies at 350 F degrees for 12-13 minutes. Remove from oven and set aside to cool.
Make the frosting
Beat together butter and cream cheese till smooth and creamy.
Add powdered sugar, 1/2 cup at a time, mixing well after each addition.
Add vanilla extract, milk and beat till frosting is smooth and everything is well combined.
Divide the frosting in 3 parts. Leave 1 part as such and color the remaining 2 with orange and black food color.
Transfer filling to a pastry bag (or you can use you spoon). Place one cookie on a flat surface, fill it with the prepared frosting and then top it with another pumpkin cookie to complete your pumpkin sandwich cookies!