Where do I buy a tagine pot to cook with?

This is the mistake I see most often, so let me be blunt: the gorgeous, brightly painted glazed tagines stacked outside every souvenir shop are made to look at and to serve from, not to cook in. Their decorative glazes can crack or leach over a flame, and they are not built for direct heat. If you want a tagine to actually cook with, you want a plain, unglazed (or simply glazed inside) terracotta tagine — humble, earthy and usually a fraction of the price of the pretty ones. It is the difference between a serving dish and a cooking pot.

For the real thing, go where Moroccans buy their cookware rather than where tourists buy souvenirs. The pottery capital Safi is the ideal source — heavy, honest cooking tagines straight from the kilns — but in any city you can find them at the kitchenware and household-goods sellers in the souk (the same stalls selling couscoussiers, tea glasses and cooking pots) rather than the polished craft boutiques. Ask specifically for a "cooking tagine," not a decorative one, and the seller will steer you to the plain ones.

When you are choosing, weight and thickness are everything. A good cooking tagine feels heavy and solid, with thick clay walls and a substantial, well-fitting conical lid — that mass is what holds and circulates the gentle heat that makes the cooking method work. Tap it to check for a clear, ring-free tone (a dull buzz can mean a crack), make sure the lid sits snugly, and pick a size you will realistically use. The unglazed clay is what gives that authentic earthy character to the food.

My practical guidance for getting it home and using it: terracotta is heavy and breakable, so wrap it very well or have it packed for shipping if it is large. Before its first use you must season it — traditionally by soaking it in water, then rubbing the inside with olive oil and baking it low and slow — and always cook over a heat diffuser on a modern stovetop, never a fierce direct flame, raising the heat gradually. Treated kindly, an unglazed clay tagine cooks beautifully for years.