Step 1

In a saucepan, melt the chocolate with butter on low heat, whisking until smooth.

Step 2

Cool slightly, remove from heat and pour into a mixing bowl.

Step 3

Mix in the sour cream, vanilla, and salt.

Step 4

Gradually add the sugar, about 1 cup at a time, until frosting is desired consistency. You may not need all 5 cups, you may need a little more.

Step 5

Frost cake.