Preheat your oven to 375ºF and prepare your half sheet pan with cake goop or whatever pan release you like.
In a large mixing bowl, combine the flour, soda, cinnamon, white and brown sugar, and set aside.
In a separate bowl, combine the eggs, milk, and vanilla and set aside.
In a saucepan, combine the cocoa powder, butter, and coffee over medium heat. Heat until the mixture begins to simmer, stirring ocassionally to prevent burning. Once it begins to boil, remove it from the heat.
Add the milk mixture to the flour mixture and mix until combined.
Add the chocolate mixture to the flour and milk mixture and mix until combined.
Bake for 15-20 minutes or until a toothpick inserted comes out from the center with just a few sticky crumbs.
While the cake is baking, prepare your glaze.