Cream shortening and sugar in a large bowl, slowly add eggs one at a time. In separate bowl sift the flour, cocoa, salt and baking soda. Gradually add to the creamed mixture and alternate with the buttermilk. Mix in the hot coffee. Drop by teaspoonfuls 3 inches apart(they spread so only put 12 on a large cookie pan). Bake at 375 for 8-10 minutes. Let them cool completely on wax paper before filling them. FILLING (I usually double the recipe) Beat (on high) the egg whites until stiff and fluffy. Gradually add the vanilla just a few drops at a time while continuing to beat. Add milk, 10X sugar and flour (in that order). Add shortening and softened butter and continue to beat until very fluffy. Take one completely cooled cookie and add 2 tablespoons (or more if you'd like) of cream filling. Top with another cookie making a "sandwich". *These freeze well if wrapped individually and last 2 month in the freezer.