oh I also make my own adaptations of this for other flavors such as strawberry, chocolate, coconut, almond, etc...
THE BEST BUTTERCREAM
2 cups shortening (I use butter instead, quite often for more flavor, but shortening is cheaper)
8 cups confectioner's sugar
1/2 teaspoon salt
1 tablespoon clear imitation vanilla extract
6 fluid ounces heavy cream
In a large bowl, cream shortening with mixer until fluffy. Add confectioners sugar (2 cups at a time) until well blended. If the frosting gets to thick at any time you can add some of your heavy cream.
Add salt, vanilla, and heavy cream and blend until combined, then blend on high until frosting is light and fluffy. If you need to add additional cream you can. (up to 2 tablespoons)
For CHOCOLATE, replace 1/2 cup confectioners sugar with 1/2 cup of coco powder, mix into sugar before adding to the butter.
For STRAWBERRY, omit vanilla extract and add strawberry instead, OR put a cup of FRESH strawberries in blender and puree, add to frosting after creaming butter and sugar but before adding cream.
For COCONUT, add coconut extract instead of vanilla, OR omit 1 cup shortening for one cup coconut oil (store and keep in cool area because the coconut oil will melt easily!)
For other flavors, either add extract of other flavor instead of vanilla, OR puree/melt and cool/ or just add softened ingredient to the butter and sugar mixture before adding heavy cream.