Cream shortening and butter with electric mixer. Add cocoa and vanilla. Gradually add 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. Keep icing covered with a damp cloth until ready to use.
Darker Chocolate Icing: Add 4 more unsweetened chocolate squares (or ¼ cup sifted cocoa powder) and 1 more tablespoon of milk to Chocolate Buttercream Icing.
Chocolate Mocha Icing: Substitute freshly brewed strong coffee for milk in recipe.
For a unique change of pace, use 1/8 to 1/4 teaspoon Wilton Candy Flavors in place of vanilla extract.
For best results, keep icing bowl in refrigerator when not in use.
Refrigerated in an airtight container, this icing can be stored 2 weeks. Rewhip before using.
YIELD: 3 cups
**Add 3-4 tablespoons light corn syrup per recipe to thin for icing cake.