Combine cocoa, sugar, salt and cornstarch, mixing well.
Add soy milk or rice milk, whisking constantly. Bring to a boil over medium heat, still whisking, then lower heat and cover. Boil gently for 5 - 10 minutes.
Remove from heat and whisk in vanilla. Pour into serving cups or prepared pie shell.
Refrigerate until thoroughly chilled and set.
Notes
Use 1/3 cup cornstarch to make Pie Filling.
Substitutions
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.