Trim any excess fat from the lamb leg and cut into 1-inch cubes.
Heat the olive oil in a heavy-bottomed pot or tagine over medium-high heat.
Add the lamb cubes and sear until browned on all sides, then remove the meat and set aside.
Reduce heat to medium and add the diced onion, sautéing for 5 minutes until translucent.
Stir in the minced garlic and grated ginger, cooking for 1 minute until fragrant.
Add the ras el hanout, cinnamon, sea salt, and black pepper, stirring constantly for 30 seconds to toast the spices.
Return the lamb to the pot and stir in the tomato puree, bone broth, and halved dried apricots.
Bring the liquid to a gentle simmer, then cover with a tight-fitting lid.
Lower the heat to the lowest setting and simmer for 45 to 60 minutes, or until the lamb is fork-tender.
Garnish with freshly chopped cilantro and serve warm.