Preparation Steps

• Preheat oven to 350°F and spray a 12×18 inch sheet pan with nonstick baking spray.
• Combine flour, sugar, and salt in a large mixing bowl. Set aside.
• Melt 1 cup butter in a saucepan over medium heat, then stir in 5 tbsp cocoa powder until combined.
• Add 1 cup hot water and bring mixture to a boil. Boil for 30 seconds then remove from heat.
• Pour chocolate mixture over flour mixture and stir to combine. Let cool for a few minutes.
• Beat together buttermilk and eggs in a separate bowl, then add baking soda and vanilla extract.
• Add buttermilk mixture to the chocolate mixture and whisk until well combined.
• Pour batter evenly into prepared pan and bake for 15 to 20 minutes or until a toothpick comes out clean.
• While cake bakes, prepare frosting. In a saucepan, bring butter, milk and cocoa powder to a boil.
• Remove from heat, stir in powdered sugar and vanilla extract, whisking until smooth and no lumps remain.
• Pour warm frosting over warm cake and spread evenly.