Start by cutting the lamb shoulder into evenly sized cubes to ensure they cook uniformly. Pat the lamb dry with paper towels—this helps with browning later. Season the lamb cubes with salt and pepper. Heat the olive oil in a heavy-bottomed pot or Dutch oven over medium-high heat.
In batches, add the lamb cubes to the hot oil and brown on all sides. This step is key to developing deep flavors. Don’t overcrowd the pot; too many pieces will steam instead of brown. Once browned, remove the lamb and set aside.
In the same pot, add the chopped onion and sauté until soft and translucent, about 5 minutes. Add the minced garlic and cook for another minute, stirring frequently to prevent burning.
Add the ground cumin, coriander, cinnamon, ginger, and turmeric to the onion and garlic mixture. Stir constantly for about 1-2 minutes to toast the spices and release their aromas. This step layers the flavor and is essential for an authentic taste.
Pour in the diced canned tomatoes and chicken broth, scraping any browned bits off the bottom of the pot with a wooden spoon. Return the browned lamb to the pot and stir to combine everything.
Add the chopped dried apricots and drained chickpeas. These ingredients add sweetness and texture to the sauce, balancing the savory spices.
Bring the mixture to a gentle simmer, then reduce the heat to low. Cover the pot and let it cook for about 1.5 to 2 hours, or until the lamb is tender and the flavors have melded beautifully. Stir occasionally and add a splash of water or broth if the sauce becomes too thick.
Taste the tagine and adjust seasoning with salt and pepper as needed. Remove from heat and sprinkle freshly chopped cilantro over the top for a burst of freshness.