Place the cashews in the blender and process briefly to grind them into a powder. (If you don't have a good blender, you can do this in a spice grinder or coffee grinder first.)
Add in the water, olive oil, lemon juice, vinegar, salt, mustard, onion powder, garlic powder, and black pepper and blend until smooth. Stop and scrape down the sides, as needed, to make sure everything gets blended. The mixture should look smooth, creamy, and runny in texture.
Add in the parsley, chives, and dill, and pulse briefly, just to incorporate them. (This gives the dressing a speckled look, like traditional ranch. If you blend too long it could turn green instead.) Taste and adjust any seasoning as needed. You may want to add up to 1/4 teaspoon more salt, or extra lemon for a more tangy flavor.
Pour the dressing into an airtight container, cover, and refrigerate for at least 30 minutes to let the flavors develop. It will thicken much more in the fridge overnight, so I recommend adding a tablespoon of water, or more, as needed to thin it out again the next day. Store in the refrigerator for up to 1 week. Shake the dressing before each use.
Nutrition is for roughly 2 tablespoons of dressing. This information is automatically calculated, and is just an estimate, not a guarantee.Recipe is adapted from Eat Dairy Free, by Alisa Fleming.Additional Notes:
If you can't tolerate cashews, hemp hearts are the easiest swap. Otherwise sunflower seeds may be used, but they have a more bitter flavor and you may need to balance that out with a little added sweetness.
Alisa's original recipe calls for a 1/2 cup of grapeseed or rice bran oil, which will help make the dressing thicker, if you'd like. I only keep olive oil on hand at home, so I used a lot less of it to lower the fat content and keep the flavor neutral. (I think the olive oil taste would be noticeable if you used more.)
If you'd like to soak the cashews for easier blending, I recommend soaking them in water for up to 2 hours, then draining and using only 1/3 cup of water in this recipe to start with. (You can always add more to thin it out later!)