Chak is a neighbourhood restaurant in Ghazoua, 8 km out of the city centre in Essaouira. I lived in this neighborhood for three weeks, and ate lunch there several times. The interior of the restaurant is, as another reviewer mentioned, rather could, but at lunch you can usually sit out in the front of the restaurant, and it is quite nice when the weather is warm enough (which really is most of the year).
The food is simple, hearty and reasonably priced. Everything (or so it seams) is imported from Italy, so I would recommend going by the daily specials, which includes a salad, a pasta dish, a meat dish or a tagine. The caprese comes with a lovely, fresh mozzarella. The pasta is fresh and al dente, and not overcooked like you'll find many other places in Morocco. The pasta dishes at Chak are usually served with a bit to much pasta sauce, for my taste, but I guess most people like this.
I see many of the other reviewers have raved about the pizzas. These are baked the roman way: thin and very crispy. Some may love this, but when it comes to pizza my heart is anchored in napoli, wich is softer, more doughier. I guess this is a matter of taste, rather than quality. What I think is a shame is the use of tinned mushrooms. I understand that fresh mushroomes are impossible to get in Morocco, but the tinned ones are awful, and I believe it would be better to drop mushrooms all together.
Chak himself is a merry man, and his wife is very sweet. If you live nearby or are on your way past this place, do by all means eat here.