Theories are all very well, but sometimes they do not tally with practice. My theory is this: that the common belief that a joint of meat stays moist if you surround it with foil, or cover it, or put it on a rack above liquid, is a fallacy. The steam does not keep the joint moist: it cooks the meat very efficiently, and so is more likely to dry it out than is the unmediated heat of a low-temperature oven. That is the theory; but when I cooked some belly pork in a casserole, it emerged beautifully succulent and tender.
All I did was chop a red cabbage and pile it into a large, oval Le Creuset casserole with four chopped apples, a couple of tbsps of red wine vinegar, some salt and pepper, and 10 juniper berries. (The acid in the apples and vinegar are supposed to preserve the colour of the cabbage, but did not -- another theory challenged by this recipe.) There was a lot of cabbage; once I put the belly pork (a 1.5 kg joint) on top, I was unable to put on the lid. So I started the cooking (without the pork) at gas mark 6/200 C for half an hour, after which the cabbage had started to collapse; I put in the pork, covered the dish, and carried on cooking at gas mark 1/140C for an hour; and then, when I was sure that everything was cooking gently, at gas mark S/130C for another two hours. Simple, and splendid. Served 6.
Perhaps my theory would work better if my oven operated at a lower temperature than 130C. As it is, the well-insulated environment of a heavy Le Creuset may offer gentler cooking.