Sopa de Mondongo is served throughout Latin America, but each country has its own version. The Nicaraguan version is characterized by the addition of sour oranges (or a mix of lime and vinegar) for cleaning and marinating the tripe, and the use of a wide range of local root vegetables.
Patience is key to this soup. The tripe and beef feet (if used) must be cooked long and slow to be incredibly tender and for the collagen to release from the beef feet, which naturally thickens the soup.
It is traditionally served with a side of white rice, avocado slices, corn tortillas, and/or Cuajada cheese.
Cut the tripe into desired large squares (about 5 cm). Place in a pot with water, add the sour orange juice/vinegar, and beef feet (if using).
Bring to a boil, simmer for 15 minutes. Drain the tripe water, thoroughly rinse the tripe, and return it to the pot. (This step helps remove the strong odor.)
To the pot with the mondongo and feet, add the beef broth, water (to cover the meat), the whole onion, garlic, sofrito (or tomato mixture), and seasonings.
Bring to a boil, reduce the heat, cover, and simmer over low heat for 2 to 3 hours until both the tripe and feet are extremely soft and tender. Remove and discard the cooked onion and garlic.
First, add the hardest root vegetables: yuca, ñame, and green plantain. Cook for 20 minutes.
Then add the potatoes/sweet potatoes/squash and cabbage. Cook for another 15 minutes until all the vegetables are soft but hold their shape.
If you want to thicken the soup (optional), mix 3-4 Tbsp of cornstarch with a little cold water and pour into the soup while stirring constantly.
Taste the soup and add more salt/seasoning if necessary. Add the fresh mint or cilantro.
Serve hot with a bowl of white rice on the side. Everyone typically seasons the soup with fresh lime juice before eating.