Preheat oven to 350 degrees F (175 degrees C). Grease cookie sheets. Sift together the flour, cocoa, baking soda and salt; set aside.
In a large bowl, cream together the shortening and sugar until smooth. Beat in the egg, buttermilk, molasses and vanilla one at a time. Gently mix in the sifted ingredients just until blended, but no more than necessary. Drop by heaping spoonfuls onto the prepared cookie sheets.
Bake for 12 to 15 minutes in the preheated oven, or until firm to the touch. Cool for a few minutes on cookie sheets before removing to cool on wire racks.