The dictionary says gratinée means "to have a covering or crust, such as buttered crumbs or cheese." When the French do potatoes gratin, they are generous with the topping ― and make sure there's plenty of cream beneath.
Our lighter alternative tastes deceptively rich, is extremely easy, and offers a a welcome respite from heavy holiday fare. The potatoes bake in a well-seasoned, fat-free broth instead of cream. A bit of cheese is added at the end for a traditional look.