The most important detail: if you are not staying at the riad, make sure to call ahead so a staffer will meet you in the main square. Dar najat is on a residential road which is barely lit; finding this place was a massive undertaking.
But we were glad we came. Service is very liesurely, and the friendly staff wants you to enjoy a complete evening. Great apps, excellent tanjine, and a refreshing fruit cocktail for dessert. Fixed menu.
Very good food at an authentic riad. If we return, I would strongly favor returning to far najat.