Lamb Tagine with Artichokes and Peas

In a large enameled cast-iron casserole, mix the oil with the salt, ginger, white and black pepper, saffron and turmeric. Add 4 of the blade chops in a single layer and cook over moderate heat, turning once, until lightly browned, about 15 minutes; transfer to a plate. Lightly brown the remaining 4 chops. Return the first 4 chops to the casserole and sprinkle the onion over the top. Tie the parsley and cilantro into a bundle and add it to the casserole along with the water and preserved lemon. Cover and bring to a boil, then cook over moderate heat until the lamb is just tender, about 30 minutes.

Meanwhile, squeeze the lemon halves into a large bowl of cold water; add the halves. Working with 1 artichoke at a time, snap off the outer green leaves. Using a sharp knife, trim the stem to 1/2 inch and cut off the top two-thirds of the leaves. Peel the bottom and stem. Scrape out the hairy choke with a teaspoon, then drop the artichoke into the lemon water.

Drain the artichokes and add them to the casserole, tucking them under and between the lamb chops, then add the peas. Cover and cook until the lamb and artichokes are very tender, about 20 minutes. Transfer the lamb, artichokes and peas to a platter and strain the juices into a small saucepan. Skim off the fat, then boil the juices until reduced to 1 cup, about 10 minutes. Pour the juices over the lamb and serve.