Published November 1, 1995.
For the easiest, most tender gratin, cook the potatoes on the stovetop in liquid, then bake them in a shallow pan.
Most recipes follow the same procedure: Rub an ovenproof dish with garlic, brush it with butter, layer it with sliced potatoes, add seasonings and just enough liquid to cover the potatoes, and bake. But we still had lots of questions: how to get the most garlic flavor, what variety of potato to use, how thin to slice it, what kind of liquid to use, and what temperature to use for baking.
Potato gratins--also known as French dauphinois or Yankee scalloped potatoes--consist of thinly sliced potatoes, covered by a liquid and baked in a wide, shallow baking pan until the potatoes are tender and the top develops a burnished crust.
For starters, we found the best way to get a stronger garlic punch was to smash the clove and vigorously rub it around the dish so that at least half of it was smeared on the surface. As for the variety of potato and how to slice it, we found the slicing--thin and, just as important, consistent from slice to slice--more important than the type of potato, which seemed a matter of personal taste. As for the liquid used, we tried making gratins with milk, half-and-half, heavy cream, broths, and water. Our favorite all-purpose liquid turned out to be half-and-half cooked at 350 degrees for about an hour. Gratins made this way had just the right balance of saturated potato and saucy liquid, without overwhelming the taste of the potato. We also adopted a technique of cooking the sliced potatoes in the cooking liquid before pouring both into the gratin dish. This method sped up the cooking process by heating the ingredients before baking, it made the assembly of the gratin much faster, and, because the seasoning was added to the liquid, it ensured that the final product was evenly seasoned.list of recipes