In a small bowl, cover the cashews with water and let sit for a minimum of 3 hours, to soften
Heat a large heavy-bottomed pot over low to medium heat. Add olive oil, onion, and ground beef.
Stir occasionally, breaking up the beef, and cook until the meat is no longer pink, and the onions are tender
Add garlic and cook a minute more
Add the tomato puree and increase the heat to medium
Drain the cashews
Add the beef broth, softened cashews, arrowroot flour, tomato paste, and salt to the blender, and puree until completely smooth.
Pour the puree into the pot, and bring to a boil. Once a boil is reached, turn off the heat, and allow to cool for a few minutes.
Serve with chopped picked and green onions