Moist mild chocolate and cinnamon flavored cake topped with a soft chocolate frosting that will melt in your mouth.
Grease and flour a sheet pan (no need for parchment paper - non-stick cooking spray and flour sprinkled and tapped around the pan will work). Preheat oven to 350°F
Sift flour, sugar, salt, and cinnamon into a large bowl.
In a sauce pan, bring butter, cocoa, and water to a boil. Pour over the flour mixture and mix on low speed.
In another bowl add eggs, baking soda, buttermilk, and vanilla. Mix together and add to the flour mixture.
Pour in prepared pan and bake for 20 minutes.
Place butter, cocoa and milk in a saucepan. Melt butter and mix but do not boil. Remove from heat.
In another bowl, combine sugar, vanilla, and nuts (if you want). Pour butter mixture into the bowl and mix until there are no lumps. Spread over the cake as soon as it is done. Let cool before serving.