In a separate bowl, whisk together the flour, salt, and baking powder. Add this to your creamed egg mixture.
Add cinnamon and quick oats. Mix well.
Add baking soda to boiling water and add this mixture to the batter. Beat until well combined.
Scoop batter onto greased cookie sheets. Bake for 10 - 15 minutes, until slightly browned.
Cool cookies on a rack.
For the Filling:
Beat egg whites, vanilla, and milk, with the whisk attachment. Add 1 cup powdered sugar and cream well.
Add remaining ingredients and beat to combine. Scrape the sides and bottom and beat on high speed until light and fluffy, at least one minute.
Sandwich the filling between two cookies to form a whoopie pie.
Wrap each whoopie pie with plastic wrap to store.
This recipe makes about 10 large whoopie pies. You can make your cookies smaller if you want to make more.The frosting contains raw egg whites. They help to create a light and fluffy frosting. But if you do not feel comfortable with eating raw egg whites just omit them. Your frosting should still turn out ok. If it's too thick just add another Tbs. of milk.
Keyword Amish oatmeal whoopie pie recipe, Pennsylvania Dutch Whoopie Pies