1. In a small saucepan, off the heat, combine the cornstarch, sugar, and salt until well mixed. Add 1/4 cup of almond milk (or another dairy-free milk alternative) and place the saucepan over medium-low heat, mixing well to dissolve the cornstarch and sugar.
2. Add the remaining two cups of almond milk, stirring constantly until mixture thickens for about three minutes. Remove the pan from heat and whisk in the margarine and vanilla until completely incorporated. Transfer pudding to individual cups and top with plastic wrap so the puddings do not get a film.