Place cashews in large jar or bowl. Cover with about 2 cups of boiling water, making sure all of the cashews are submerged. Let soak for 20 minutes. Pour cashews and liquid into a fine-mesh strainer to strain the soaking liquid. Rinse.

Drain the water and discard. Place drained cashews in the pitcher of a blender. Add 1 cup of water, vanilla if using, and salt if using. Blend until completely smooth, about 1 minute, adding more water a couple of tablespoons at a time if needed to get it moving. Add additional water, up to another 1/2 to 1 cup or so, until it's the creamer is consistency you like. I go for a rich and creamy, half-and-half-ish thickness. But also know that your cashew creamer will thicken in the fridge.

Use in coffee just as you would any other creamer. Keeps refrigerated in an airtight container for about 5 days. It might separate in the fridge; simply shake before pouring.