Sift together baking soda, flour, salt and sugar. Melt together cocoa, shortening, and boiling water. Mix the dry ingredients into the cooled mixture to blend. Add eggs, buttermilk and vanilla.
Bake in either layers at 350ºF for 25 minutes or in an oblong pan for 40 - 45 minutes.
Mix sugar, milk and flour well and cook to a thick paste. After cooling, add Crisco, sugar, marshmallow cream, and vanilla. Mix the two and beat together on high speed for 15 minutes. This may also be colored of desired.