Whoopee Pie Filling

 
2
3/4
3
1/8
1/2
2+
TBL
Cups
Cups
Tsp
Tsp
TBL
Egg White Powder ***
Hi Ratio Shortening (same as 12 Tbl) **
Powdered Sugar
Salt
Vanilla
Milk

 
Double the above or make second batch with peanut butter for 16 inch recipe.
 
Mix on high for 15 minutes until smooth, DO NOT SHORT TIME THIS!!!
Add milk to reach your choice of filling preference. 
Give about 5 minutes for the filling to start to fluff up .
 
After cookies are cold, spoon filling between the two cookies.

** Hi Ratio shortening is used by bakers and is fluffier and reduces grease taste.

** Sub peanut butter or unsalted butter for 1/2 cup of shortening, if desired

***  The use of raw egg whites may be a concern, so use Wilton egg white
powder.  The original filling had 2 egg whites instead of powder, or you can
omit and have less volume.  Also, the eggs in the dough was just yokes,
saving the whites for filling.