In large bowl, beat shortening and butter with electric mixer on medium speed until combined. Add dark cocoa powder or melted chocolate and vanilla.

Gradually add confectioners’ sugar, one cup at a time, beating well on medium speed. Scrape sides and bottom of bowl often. When all sugar has been mixed in, icing will appear dry.

Add milk and beat at medium speed until light and fluffy. If icing is too stiff, add additional milk, 1 teaspoon at a time, until icing reaches desired consistency.

Keep icing covered with a damp cloth until ready to use.