In a stand mixer, whip your butter chunks and brown sugar on medium high speed until the butter is light and fluffy and the brown sugar is incorporated.
Add in the powdered sugar 1 cup at a time, letting it mix into the butter completely.
Add in the vanilla, heavy cream, and pinch of salt, allowing the ingredients to incorporate fully
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 if 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.
Enjoy! (I like to use this recipe to frost my Sweet Potato Cupcakes!)