Okay, so DH requested scalloped potatoes for dinner last night, so I found this thread with this recipe posted by Gail:
JULIA CHILD'S POMMES DE TERRE DAUPHINOISE
Yield: A large casserole, serving 6 to 8
1 teaspoon salt, plus more if needed
1 teaspoon chopped garlic
3 cups milk, or mixed milk and cream, plus more if needed (Gail note: the sky’s the limit here. Julia says you can do anything from nonfat to full cream. I’ve done this with mostly cream and it is WONderful.)
½ teaspoon freshly ground white pepper, plus more if needed
2 pounds boiling potatoes, peeled and covered in water (Gail: recommend Yukon Golds)
1 to 2 tablespoons butter for topping potatoes, optional (Julia recommends doing this if you go the nonfat route.)
A food processor with a slicing disk (optional); and 8 to 10 cup flameproof gratin dish, lightly buttered; a cookie sheet.
Preheat the oven to 400º F. Slide the rack on the lower third level and set the cookie sheet on it to catch boil-overs.
Sprinkle ½ teaspoon of salt on the chopped garlic and mash together with the blade of knife, to make a purée. Pour half the milk (or milk and cream mixture) into the gratin dish and add the garlic purée and the rest of the salt and the pepper.
Cut the potatoes crosswise, by hand or in food processor, into very thin slices (1/8 inch or less)—do not rinse them again. Spread them evenly in the gratin dish and pour in the remaining milk. The liquid should come right to the top layer of potatoes—add more milk or cream if needed.
Place the dish on a burner, bring to a slow boil, and cook for 2 to 3 minutes, until the liquid has thickened slightly. Scrape the bottom gently with a wooden spoon to prevent scorching. Taste the liquid and adjust the seasoning.
Turn off the heat and dot the top of the gratin with a tablespoon or two of butter, if you wish. Place the dish in the oven, on top of the cookie sheet, and bake for 40 to 50 minutes, until the top is nicely browned, most of the liquid has been absorbed, and the potatoes are tender all the way through when pierced with a knife. If not served at once, keep warm in a turned-off oven or set over a pan of simmering water.
(Gail note: I didn’t have a suitable for burner dish, so I heated the milk and cream, plopped in the garlic paste, heated a bit more, then poured half in dish, added potatoes and added remaining liquid. This stuff is good even at room temperature or—I kid you not—out of the fridge. Sinful. Also on my menu again for Christmas dinner.)
I used 2 cups of milk and 1 cup of cream, then heated in a sauce pan. They baked in the oven for about 45 minutes, then I turned the oven off so they could stay warm while I finished some other things. They stayed in the warm oven for an additional 15 minutes. When I took them out, the sauce had separated…water underneath, with a “creamy” clotted layer on top. The taste was great, but the texture was definitely off-putting. So what did I do? Did I use too much milk? Did I cook them too long? Were my potatoes not starchy enough or something? We really liked the flavor of this, so I'd like to make them again, but with a better consistency!