Gluten Free Whoopee Pies w/Buttermilk 
2/3 Cup Potato Flour
1/3 Cup Arrowroot
2 Cup Rice Flour
2 Tbl Buttermilk Powder *
1 Tsp Gluten Free Baking Powder **
1 Tsp Salt
1/2 Cup Cocoa Powder (types of cocoa)
1 1/2 Cups Sugar
1 Tsp Baking Soda
1 1/2 Cup Hot Water
1/2 Cup Shortening (same as 8 Tbl) (Not Hi Ratio)
3 Egg yokes
1 Tsp Vanilla
* For real Buttermilk, leave off buttermilk powder and 1/4 cup hot water, use 1/2 cup Buttermilk.
** If you do not have Gluten Free, use 1/3 tsp soda and 2/3 tsp cream of tartar
Blend Flours and Buttermilk powder before starting.
Mix  all dry, then add rest and blend.  Should be like pancake batter.
Add water as needed.
Spoon on parchment paper, same as making cookies. 
Bake 350 for 20-35 Minutes. Top will spring back when touched.
Toothpick test works on this type.
Do not use silicone pans, will not cook as well.

3 Egg Whites
3/4 Cups Hi Ratio Shortening (same as 12 Tbl) **
3 Cups Powdered Sugar
1/8 Tsp Salt
1/2 Tsp Vanilla
  2 TBL Milk - add enough to make smooth and fluffy    

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

Mix on high for 15 minutes until smooth, DO NOT SHORT TIME THIS!!!
After outsides are cool, spoon filling between two above cookies

Check on effects of cocoa types here