In a large bowl, mix together the flour, baking soda, cocoa powder, and salt.
Then mix in the other ingredients.
Mix well, so everything is well incorporated.
Then spray your whoopie pie cavities (see my suggestions under Kitchen Items used) Fill your cavities with the batter.
Set in the air fryer oven/basket for 5 minutes at 320 degrees F.
Let the whoppie pies cool slightly, meanwhile make the filling.
In a large bowl, mix together the shortening, powdered sugar, Marshmallow Fluff, and salt, mix well.
Then place a scoop of filling onto one side of the whoopie pie, use another one to close it an make a sandwich.
Plate, serve and enjoy!