In a medium pot, heat 1 cup chicken broth to a boil. Once boiling, turn off heat, and add the cashews. Set aside.
In a large heavy bottom saucepan, cook bacon until crispy. Pour out all but 2 tablespoons of the bacon grease. Allow bacon to cool on a plate lined with paper towel. Once cool, roughly chop.
Heat bacon grease to medium. Add onion and celery and cook until just soft, about 6 minutes. Add garlic and stir for 1 minute.
Sprinkle tapioca starch, stir. Add remaining chicken broth, stir. Add potatoes, clam juice, and bay leaf. Bring to a boil and simmer for 15-20 minutes, stirring occasionally.
Blend cashew/broth mixture in a high speed blender until smooth. Add to the saucepan.
Add salt, pepper, cayenne, and sherry vinegar. Stir well. Simmer a few more minutes and serve with bacon and chives.