Heat the extra virgin olive oil in a heavy-bottomed pot or tagine over medium-high heat.
Add the cubed lamb leg and sear until browned on all sides, then remove the meat and set it aside.
In the same pot, sauté the diced yellow onion and minced garlic until softened and translucent.
Stir in the ground cumin, coriander, cinnamon, ginger, sea salt, and black pepper, toasting for 30 seconds until fragrant.
Return the lamb to the pot and add the chickpeas, tomato puree, and beef broth.
Bring the mixture to a gentle simmer, then reduce heat to low, cover, and cook for 45 minutes until the lamb is tender.
Garnish the tagine with chopped fresh cilantro before serving hot.