A couscoussier is a type of traditional North African cookware which allows a cook to steam couscous while simultaneously preparing the stew which will be served atop it. It looks very much like an over-sized double boiler, except that the top piece is a large steaming basket with holes in the bottom. Inexpensive, lightweight aluminum couscoussiers are most prevalent in Morocco, but clay and stainless steel ones are also available.
How to Steam Couscous shows how to work specifically with couscous; below, however, are general tips for using the couscoussier itself.
The Stockpot Bottom
The bottom or base of the couscoussier (barma) is essentially a large stockpot, often with slight contouring at the rim. As such, it can be used alone to make soups, broths. and stews other than what you might make to serve with couscous. You can use it to boil pasta, too.
The Steaming Basket
A large steaming basket (kesskess) sits atop the base. Although the holes in the bottom are larger than those in a typical colander, the fine grains of couscous do not fall through. The kesskess does not nestle deep inside the pot like some styles of steaming baskets, but rather fits snugly just inside the rim. This allows ample space in the pot below for cooking voluminous quantities. In addition to couscous, the basket might be used to steam other foods such as broken vermicelli (chaariya) when making seffa; shredded msemen when making rfissa; spinach or mallow leaves when making cooked salads; as well as poultry, meats, rice, and vegetables.
General Tips for Using a Couscoussier
1. Be sure the steam is rising only from the top of the basket and not escaping from the joint between the basket and base. If necessary, seal the joint. The easiest way to do this is to take a very long length of plastic wrap or kitchen film (you might try using aluminum foil instead), fold it in half lengthwise once or twice, and then drape it and fit it around the rim of the stockpot base.
Be sure that the film covers the full circumference of the rim. Set the steamer basket on top and nestle it snugly into the plastic-wrapped rim. You can leave the plastic wrap seal in place when you lift off the basket in between steamings.
2. Don't let the liquid in the stockpot touch the steamer basket. When making a couscous recipe with lots of veggies, the stockpot base can fill up quickly, pushing the level of the broth way up. Be careful that it's not so high that the broth will reach the steaming basket when it comes to a boil. If necessary, consider cooking half of the stew in the couscoussier base and the other half in a separate pot. This is particularly useful when feeding a large crowd or when you want to ensure that there is ample sauce to offer on the side.
3. Don't pack the steaming basket. This doesn't mean that you can't fill the kesskess to the brim with couscous, but rather that you ease the couscous gently into the basket when filling it and avoid compressing it. By the third and final steaming of couscous, for example, the grains will be quite plump and voluminous. In this case, you can add the couscous in several increments, waiting for steam to rise from each addition of couscous before filling the basket a little bit more.
4. Don't cover the steaming couscous. Or do cover. There is a difference of opinion as to whether or not you should cover couscous when steaming it. I prefer not to, as I feel uncovered couscous absorbs more broth (and hence more flavor) at serving time, but other cooks believe that covering during steaming further plumps and tenderizes the couscous. It's really up to you. Try it both ways and see which you like better.