Refrigerate for 15-20 minutes to allow it to thicken up before using to decorate if needed. If the frosting is too thick after refrigerating, it will soften up quickly at room temperature. or to speed things along you can stick it back in the mixer and mix for a few seconds. If the frosting is too runny, add more powdered sugar to thicken it.
*You can add any other extract you want (lemon, lime, orange!!). *If adding food coloring you can add it in with the vanilla and heavy cream, or if you need multiple colors, separate the frosting when done and then mix in the coloring.