Add the meat, broth and 250ml water to a large pan. Bring to a boil, reduce to a simmer and cook for 30 minutes.
Add the plantains, onion and tomato to the pan, cover, and simmer on low heat for about 35 minutes, or until the ingredients are soft.
Mash with a fork and potato masher to make a creamy soup (you can also take the beef out and use a hand blender).
Return the beef to the soup, and re-heat. Adjust the seasonings and serve immediately in soup bowls.