Place shortening in stand mixer. slice open vanilla bean the long way and use knife to scrape out all seed bits on to shortening and place on medium speed. Add sea salt and slowly alternate powdered sugar and rice milk and whip several minutes until fluffy.
Use 1/2 to 1 cup safe milk to achieve desired consistency as the type of "milk" and type of "butter" used will cause variation in texture.
Best made a few hours ahead of frosting so the vanilla bean can permeate and flavor the frosting!
Notes
This recipe is Corn free when made with Spectrum Shortening, Wholesome Sweeteners or Trader Joe's corn free powdered sugar which uses tapioca starch, and home made or Original Classic Rice Dream
Use any brand of shortening, powdered sugar, and rice milk or other milk alternative or water to make this frosting safe for your allergy set.
Corn Substitutions: Corn is a common ingredient in products. Starch, modified food starch, dextrin and maltodextrin can be from corn. Consult with your physician to find out which corn derivatives you need to avoid. Many corn-free options are available in the US. Find out more about corn substitutions.
Milk and Soy Substitutions: Alternative dairy-free milk beverages and products will work in most recipes. Find out more about milk substitutions and soy substitutions.