Yesterday I posted a photo and brief description of the dish of "baker's wife potatoes" that I made a few days ago. Here's the recipe, translated from the French recipe I use. It's what's called a gratin in French, or a kind of scalloped potatoes in English — "to scallop" means to cut a vegetable or meat (veal scallopini, for example) into thin slices.
Pommes de terre à la boulangère
2 to 2½ lbs. baking potatoes
2 medium onions (about 10 oz. by weight)
2 to 3 Tbsp. butter for the onions
1 to 1½ Tbsp. butter for the baking dish
3 cups broth (chicken or other)
salt and pepper to taste
a teaspoon or sprig of thyme
The key to getting the potatoes done right is to put in just enough broth to moisten and tenderize them as they cook, but not so much that they are swimming in it. If you put in too much, there's always the possibility of pouring some off (don't burn yourself!) or sucking some out using a turkey baster toward the end of the cooking time, to let the potatoes dry out a little.
Put the broth on to heat up. Slice the onions and cook them on low heat in butter for 20 minutes.
Peel the potatoes and cut them into thin slices.
Butter a baking dish and arrange the potato slices and cooked onions in it in several layers. Season each layer with salt, pepper, and thyme. Pour on enough of the broth to not quite cover the potatoes.
Put the dish in the oven at 350ºF (180ºC) for about an hour. Keep at eye on it to make sure the potatoes don't brown too much or dry out. Add more (broth or water) as needed.
Test the potatoes for doneness by piercing them with a fork or a skewer. Serve hot.
In his book on cooking potatoes — Le Meilleur et le plus simple de la pomme de terre : 100 recettes — French chef Joël Robuchon writes: "In times gone by, it was the custom to cook potatoes this way in the same pan with a roast of lamb or pork, so that the potatoes would be flavored by the meat juices as they cooked."