Add the cashews, water, pickle juice, lemon, hot sauce, garlic, mustard and salt to a blender.
Blend on high until smooth
Add the onions, pickles and parsley to the blender.
pulse until well chopped and incorporated.
Notes
If you are not using a high speed blender, you can soak the cashews overnight, boil them for 30 minutes or grind the dry cashews into a fine powder using a coffee grinder (do not boil them for this method).
Stone ground mustard gives the best flavor but you can also use dijon.
I did not need extra salt but you may if your pickles are not very salty.
Recipe makes 2 ½ cups. Serving size is 2 tablespoons.