When using milk substitutes, the custard will not have as rich, creamy and velvety texture. As well it can have a bit of a watery aftertaste. So be sure to add a flavoring to boost the taste.
If custard is slow to thicken, or isn't as thick as you'd like, mix together another Tbsp of cornstarch with 1 Tbsp more of almond milk then pour into saucepan.Whisking until thickened