Heat the olive oil in a heavy-bottomed pot or tagine over medium-high heat.
Brown the cubed leg of lamb on all sides until a golden crust forms, then remove the meat and set it aside.
In the same pot, sauté the diced onion and minced garlic for 3-4 minutes until translucent and fragrant.
Stir in the cumin, coriander, cinnamon, ginger, salt, and pepper, toasting the spices for 30 seconds to release their oils.
Return the lamb to the pot and add the beef broth, diced tomatoes, chickpeas, and chopped dried apricots.
Bring the mixture to a gentle boil, then reduce heat to low, cover, and simmer for 45-60 minutes until the lamb is tender.
While the lamb is simmering, cook the pearl couscous in a separate pot of boiling water for 8-10 minutes, then drain.
Fluff the couscous with a fork and serve the lamb tagine directly over the grains, garnishing with freshly chopped cilantro.