Cream together 2 cups sugar, 1/2 cup shortening and eggs. Combine 1 cup milk plus 1 teaspoon vinegar. Add to mixture with vanilla, blending well. Set aside.
Mix together flour, baking soda, salt, baking powder, and cocoa in a separate bowl. Gradually add to creamed mixture until well blended. Finally add the boiling water and mix well.
Drop by rounded teaspoonful on to ungreased cookie sheets. Bake for 5 minutes. Remove to baking rack to cool.
Cream margarine and shortening. Add 1 cup milk and 1 teaspoon vanilla, continuing to beat. Slowly add pudding mix and 1 cup confectioners' sugar.
Assemble cookies by spreading filling on one side of cookie and then placing another on top.
