Combine butter & sugar in a large mixing bowl- beating on medium speed.
Add egg & vanilla. Beat in on low.
Slowly beat in flour- one cup at a time.
Add cocoa powder & the pinch of salt. Mix well on low.
Transfer dough to a sheet of parchment paper & then lay another piece on top to sandwich the dough between the two sheets.
Roll a rolling pin over the top of the parchment until the dough is in a flat piece.
Freeze for about 10-15 minutes.
Preheat oven to 350 degrees.
Remove dough from freezer & cut into your shapes & transfer to a parchment-lined baking sheet.
Bake for 10-13 minutes. I did mine for 13 because I made them thick.
Cool on the baking sheet & then transfer to wire rack.
Pipe on Royal Icing if desired.