Preserved lemons are pickled in salted lemon juice. They can be mail-ordered from Kalustyan's, 212-685-3451.
A tagine refers to both a Moroccan stew and the earthenware pot in which the stew is traditionally cooked. The pot's cone-shaped lid traps steam, helping produce a succulent stew. Dutch ovens and other heavy pots also work well for preparing tagines.
To clear space on the stove, you could cook the tagine in a 300° oven after bringing the stew to a boil. If the stew bubbles too rapidly once it's in the oven for 10 minutes, turn down the heat.
A full-flavored red is the perfect match for the succulent lamb here. Look for a fruity, spicy Côtes-du-Rhône or a North African red from Tunisia.