Add the powdered sugar, vegan butter, salt and vanilla extract to the bowl of a stand mixer and starting at slow speed, gradually increase speed until thick and smooth.
If your consistency is too thick, add a little non-dairy milk a drop at a time, and if it's too thin, add ¼ to ½ cup more powdered sugar.
Spread onto cakes or pipe onto cupcakes.
Store leftovers in the fridge.
