This is the chocolate frosting recipe that I use. It has a good chocolate flavor and crusts good, too. I am not sure exactly how many cups this makes, but I had enough to frost a 2-layer 8-in cake that was torted and had some leftover. If you don’t need a ton it can be halved also.
2 cups butter, softened (I use unsalted butter)
9 cups powdered sugar
2 1/2 cups cocoa powder
1 teaspoon vanilla
1 cups milk
Cream butter in a large mixing bowl. Gradually add powdered sugar and cocoa powder. Add vanilla and milk until desired consistency.