Measure water and add salt; stir to dissolve and set aside.
Put flour, cocoa powder, and cinnamon into stand mixture fitted with paddle attachment. Turn mixer on low for about 30 seconds.
Coarsely dice all butter and place in stand mixer on top of flour. With mixer on low, slowly drizzle in water. Watch closely as dough will start to pull together after about 1 minute. Once the dough forms a ball stop the mixer.
Flour work surface and remove all the dough from mixer bowl.
Roll dough into a rough rectangle, dusting with more flour if the dough gets too sticky.
Fold the dough in half, then in half again, then in half again. Wrap in plastic and chill for about one hour.