For the Lamb: In a large Dutch oven or heavy-bottomed pot, heat oil over medium-low until shimmering. Add onions, cover, and cook, stirring occasionally, until onions are soft and translucent, 10 to 15 minutes.

Add garlic, turmeric, ginger, coriander, salt, and pepper and cook, stirring occasionally, until fragrant, about 3 minutes.

Add lamb pieces and stir to combine with onions and spices, then add stock or broth and cilantro bunch. Increase heat to medium-high and bring to a boil, then cover pot, reduce heat to low, and simmer, adjusting heat as needed to maintain a gentle simmer and stirring every 30 minutes to prevent sauce from sticking to bottom of pot, until meat is tender and separates easily when pressed with a fork, 2 to 2 ½ hours. Sauce may thicken slightly during cooking, but pan should not be dry; if necessary, add more stock or water, 1 tablespoon at a time, until there is at least half an inch of sauce in pan. Season with salt to taste.

For the Caramelized Prunes: Once meat is cooked, in a medium saucepan, add prunes, vegetable stock, honey, olive oil, cinnamon, salt, and pepper and bring to a simmer over medium-low heat. Gently simmer until sauce thickens slightly into a dark syrup, about 7 minutes. Season with salt to taste.

To Serve: Discard cilantro bouquet from the lamb. Transfer lamb tagine to a serving bowl then arrange prunes with their syrup over lamb. Garnish with toasted sesame seeds and cilantro leaves. Serve with your choice of bread, couscous, or rice.