Preheat oven to 400-degrees.
In a mixing bowl, add flour, sugar, baking soda and salt; set aside.
Next, add baking cocoa, butter, vanilla extract, and water to the saucepan, bring it all to boil.
Once the butter mixture has come to a boil slowly add to the flour mixture. Set mixer on low while combining all the butter mixture.
Slowly add one egg at a time as the mixer is on low speed.
Mix in the sour cream, scrap the sides of your mixing bowl to make sure all the ingredients are combined.
In a medium-size saucepan, add butter, baking cocoa, and milk.
Cook this until mixture starts to bubble, remove from heat, and add vanilla extract.
Pour Frosting over cake let set up and serve