Make the meatball mixture

• In a bowl, combine the ground beef, rice, egg, grated onion, garlic, chopped mint, salt, pepper, cumin and oregano.
• Mix with your hands until everything is evenly incorporated.
• Roll the mixture into small meatballs and set them aside.

Build the tomato broth

• Blend the tomatoes with a piece of onion and a splash of broth until smooth.
• Heat the oil in a stockpot and pour in the tomato mixture.
• Cook it down until it darkens and thickens slightly.

Simmer the soup base

• Pour the remaining broth into the pot and bring it to a boil.
• Add the chopped onion, carrots, potatoes and corn.
• Season with salt and simmer until the vegetables start to soften.

Cook the meatballs

• Gently drop the meatballs into the simmering broth one by one.
• Cover and simmer until the meatballs are cooked through and the rice inside is tender.
• Skim any foam from the surface.

Finish with the vegetables

• Add the zucchini and simmer until just tender.
• Taste and adjust the salt.

Serve

• Ladle the soup into bowls, making sure each gets meatballs and vegetables.
• Top with cilantro and serve with lime wedges.