Use a hand mixer or stand mixer to cream butter and vanilla together.
Add ½ cup of powdered sugar and mix well.
Add more powdered sugar ½ cup at a time until frosting reaches desired consistency.
Add heavy cream to the butter and sugar mixture and mix. Frosting should be smooth but hold its shape fairly well.
Pipe onto room temperature cupcakes or spread on top of cake layers. Top with sprinkles, fruit, or fresh mint.
Notes
This recipe makes enough for a dozen cupcakes or a one-layer cake. Double the recipe for a two-layer cake. If you want to pipe taller piles of frosting on your cupcakes, you should 1.5x or double this frosting recipe. To make chocolate buttercream frosting: Replace ½ cup of the powdered sugar with ½ cup of unsweetened cocoa powder.