Add all ingredients to a high-powered blender and blend until smooth. This takes about 5 minutes in my Vitamix and you may need to use a tamper. If the result is not a creamy, smooth sauce (it is still grainy) or if there isn’t enough liquid for your blender to whip the sauce smooth, you can add additional water (1 to 3 Tbsp is usually sufficient -- add one tablespoon at a time and blend after each). Note: The soak time of your cashews and/or your brand of blender will affect how much water is needed to make this sauce lusciously smooth.
Taste and adjust seasoning to your liking. You may need additional ginger or lemon juice depending on your tastes.
You can also add extra water to turn this from a thicker sauce into more of a thinner dipping sauce.