Heat the olive oil in a heavy soup pot over high heat.

Add the lamb and brown lightly, stirring occasionally, for 5 minutes.

Add the chopped onion and continue to cook until the lamb is thoroughly browned and the onions are softened and colored, about 7 minutes more.

Spoon off all the fat from the pot.

Add the beef broth and bring to a boil.

Reduce the heat to low, cover, and simmer until the lamb is tender, about 1 hour and 15 minutes.

Refrigerate the soup, uncovered, until the fat rises to the surface, about 40 minutes.

Skim the fat away.

Bring the soup to a boil over medium heat.

Add the diced turnip, zucchini, carrots, bell peppers, tomatoes, cumin seeds, chilis, and crushed coriander.

Cook, covered, for 20 minutes.

Add the chickpeas and cook for 10 minutes more.

Remove the chili peppers from the soup.

Add salt and vinegar.

Taste and add more salt and vinegar, if desired.

Let stand, covered, for 10 minutes.

Serve the soup garnished with fresh cilantro.