In a high-speed blender, combine the soaked cashews, water, lemon juice, nutritional yeast, Dijon mustard, capers, garlic powder, onion powder, salt, and black pepper.
Blend on high until the mixture is completely smooth and creamy, scraping down the sides as needed.
Taste and adjust seasoning if necessary, adding more lemon juice for tang or salt for flavor.
Transfer the dressing to an airtight container and refrigerate for at least 30 minutes to allow the flavors to meld.
Serve over your favorite salad, or use as a dip for vegetables.