Add oxtail and water or stock to a large stockpot. Cook over medium-high heat and then bring to a boil before simmering for about half an hour. Remove any foam or debris from the top of the liquid.
Transfer the oxtail and broth to a pressure cooker or Instant Pot. Turn it on high pressure and set it to 35 minutes. Once the soup has cooked, let it release pressure before proceeding.
Transfer the broth into an oil separator to remove extra fat. If you do not have an oil separator, you can also just let the broth sit for ten minutes before skimming the top with a ladle.
If you don’t want to serve your oxtail with bones, you will need to let it sit for about half an hour to cool. You can then remove the meat from the bones and break it into smaller chunks.
Heat your stockpot, adding onions and carrots once it has warmed. Cook until the onion softens, about fifteen minutes or so. Then, transfer the beef broth and beef meat back to the big pot. Add your ginger, potatoes, cabbage, tomato, tomato paste, and spices. Simmer for about forty minutes.
Transfer the soup to bowls, then garnish with heavy cream or yogurt.