Put 2 tablespoons of the olive oil in a bowl and add the diced lamb. Toss the meat in the oil to ensure it is evenly coated, then set the bowl aside.

Take a large resealable bag and add the dried herbs and spices to it – the cinnamon, paprika, turmeric, cloves, cumin, cayenne pepper, salt, cardamom, garlic powder, saffron, ginger, and coriander. Mix the herbs and spices well, add the lamb cubes to the bag, and toss the combination to ensure the meat is entirely coated. Seal the bag and put it in the refrigerator overnight, or for a minimum of 8 hours.

Once the lamb has been refrigerated overnight, use a heavy-bottomed pot to heat 1 tablespoon of oil over a medium-high heat. Divide the lamb cubes into three batches, and brown each batch in the heavy-bottomed pot. Once browned, transfer the lamb cubes to a plate.

Add the carrots and onions to the pot and cook them for 5 minutes before stirring in the ginger and fresh garlic. Cook for a further 5 minutes. Put all the lamb cubes back into the pot and add the honey, chicken broth, lemon zest, and tomato paste. Stir the pot well, and bring it to the boil. Once it is bubbling, reduce the heat to low, cover the pot, and simmer for 1½ to 2 hours. Make sure you stir the pot occasionally, and check that the meat is tender.

Check the consistency of the tagine near the end of the cooking time. If it is thinner than you would like, combine the cornstarch with water to make a paste and add to the pot during the final 5 minutes, stirring well.

Serve with rice or couscous, with Moroccan flatbread on the side.