Step 1

Preheat the oven to 350F degrees. Lightly grease and flour a 9x13 inch baking pan.

Step 2

Add the butter, cocoa powder and water to a medium saucepan over low-medium heat.

Step 3

Melt everything together while gently whisking until the cocoa powder is dissolved and the butter is melted. Remove from the heat.

Step 4

Pour into a large mixing bowl and allow to cool slightly.

Step 5

Mix in the sugar, followed by the eggs and vanilla extract.

Step 6

With the mixer on low beat in the flour, baking soda and salt. Then mix in the sour cream.

Step 7

Pour into the prepared pan and bake for about 35 minutes until an inserted toothpick comes out clean. (I usually start checking around 30 minutes just in case).

Step 8

Melt together the butter and cocoa powder in a small saucepan over medium heat.

Step 9

Remove from the heat and pour the mixture into a mixing bowl to cool slightly.

Step 10

Beat in the powdered sugar about 1/2 cup at a time, alternating with a tablespoon of the milk/cream until the desired consistency and sweetness is reached.

Step 11

Frost the cooled cake, and optionally decorate with sprinkles.