Step 1

Preheat oven to 400 degrees F. Grease 2 cookie sheets.

Step 2

To make the cookie, add white sugar and shortening in a bowl and mix until fluffy. Beat in the eggs one at a time. Stir in sour milk and vanilla.

Step 3

Combine the cocoa, flour, and salt. Pour into the batter and mix well.

Step 4

In a separate bowl, add baking soda and hot water and mix until dissolved. Add the mixture into the batter.

Step 5

Scoop tablespoonfuls of batter onto the greased cookie sheet.

Step 6

Bake at 400 degrees Fahrenheit for 8 minutes or until firm. Do not overbake.

Step 7

Let cookies cool for a few minutes and then transfer to a wire rack. Allow cookies to cool completely.

Step 8

For the filling, combine shortening, sugar, and flour in a bowl. Mix together until light and fluffy.

Step 9

Gradually beat in the milk and vanilla and mix well. Fold in the egg whites.

Step 10

When your cookies have cooled completely, sandwich a tablespoon (or more) of filling between two cookies.

Step 11

Enjoy!