In a medium saucepan, whisk together cashew milk, maple syrup, cornstarch, and optional turmeric until smooth, over medium heat.

Bring the mixture to a simmer, whisking continuously for about 5 minutes until thickened and coats the back of a spoon.

Remove from heat and stir in vanilla extract or vanilla bean seeds.

Transfer to a heat-proof dish, whisk until smooth, cover with plastic wrap, and cool at room temperature for about 20 minutes.

Refrigerate for at least an hour to set fully, whisk to restore consistency before serving.