Ice these delicious cookies after they have cooled.
In a large bowl, sift together flour, cocoa, salt, and cinnamon. Set aside.
In the bowl of an electric mixer fitted with the paddle attachment, cream together butter and sugar until fluffy. Beat in eggs and vanilla.
Add flour mixture; mix on low speed until thoroughly combined. Divide dough in half; wrap in plastic. Chill at least 1 hour.
Heat oven to 350 degrees. On a well-floured board, roll out dough to 1/8 inch. Cut into desired shapes. Place on ungreased baking sheet and chill until firm, about 15 minutes. Bake for 8 to 10 minutes, or until crisp but not darkened. Cool on wire racks and decorate with Royal Icing.