Mix together the flour, leaveners, spices, and salt until well blended. Combine the wet ingredients in a separate bowl until fully mixed.
Cream the butter and sugars until light and fluffy.
Add in the wet and dry mixtures and beat until batter is smooth and combined.
Scoop whoopie cookies and drop at least 2” apart on prepared pans. Bake until fully set and brown on the bottom.
Beat together all the icing ingredients until smooth.
Marry the whoopie pies by matching all the cookies up with a similarly sized/shaped partner. Add 1-2 tablespoons of frosting on top of bottom cookies.
Sandwich the filling by placing the second cookie on top and pressing it down until the filling comes just to the edge of the cookies, then enjoy!