(may increase to 5 cups if you want stiff/ crusting icing)
Beat shortening until light and fluffy.
Add icing sugar and whipping cream in two parts, alternating between the two.
Beat in vanilla. Result should be icing with stiff peaks.
If applicable, add in your food coloring of choice
Optional: Add 1 tbsp (at a time) of milk to make a thinner consistency of icing.
Double the recipe if you are icing a layered cake
5 cups of icing gives you a crusting buttercream, which is great in small quantities such as when you are icing cupcakes, small details on cake as it holds it shape for longer.
However, 5 cups of icing may be too sweet for a cake (especially for your guests!), I recommend reducing it down to 3 cups if you prefer less sweet Buttercream.