Heat the olive oil in a large heavy-bottomed pot or Dutch oven over medium-high heat. Pat the lamb chunks dry with paper towels and season them generously with salt and black pepper.

Add the lamb to the pot in batches to avoid overcrowding, searing until deeply browned on all sides, about 5 to 7 minutes per batch. Transfer the browned lamb to a plate and set aside.

Reduce the heat to medium and add the chopped onion to the pot. Sauté until softened and translucent, about 5 minutes, using a wooden spoon to scrape up the flavorful browned bits from the bottom.

Stir in the minced garlic and Ras el Hanout spice blend. Cook until highly fragrant, which should take about 1 minute.

Return the browned lamb and any resting juices to the pot. Pour in the undrained diced tomatoes and beef broth, stirring well to combine all the ingredients.

Bring the stew to a gentle boil, then immediately reduce the heat to low. Cover the pot with a tight-fitting lid and let it simmer gently for 1 hour.

Stir in the halved dried apricots and continue to simmer covered for an additional 30 to 45 minutes, or until the lamb is incredibly fork-tender and the sauce has thickened.

Taste the tagine and adjust the seasoning with additional salt or pepper if desired. Serve hot over warm, fluffy couscous, generously garnished with toasted slivered almonds and fresh cilantro.