Whisk the non-dairy milk with cornstarch, sugar and turmeric (if using) in a medium, heavy-bottomed pan. Add in the saffron strands, bring to a gentle simmer, lower the heat and keep stirring the mixture will start to thicken, it should take about 10 minutes or so.
You can check it by sticking a wooden spoon in the sauce, and it if coats the back of the spoon, it’s good. Remove from heat and whisk in the vanilla paste or extract.
Pour the custard into a glass or other non-reactive bowl and place in the fridge to thicken for a couple of hours. Once it has cooled you can cover the surface with plastic to prevent a skin forming on top.
Either serve as is with fruits, and nuts or use in your recipe as directed.