The technique of cooking food long and at a bare simmer (or at low oven temperatures) has hit the home cooking world like any new fad hits the world. Inevitably, the new way is “better” and the results are “fantastic”. Few people ever try to compare things and methods.
I agree that slow roasting often yields fine results, especially with otherwise somewhat uneven cuts like chunks of pork shoulder: a quick roast of pork shoulder is an inhomogeneous affair of wobbly, undissolved fat and dry-ish sections of tasteless meat, a slow roast of the same cut provides a completely disintegrating yummy heap of fatty delight instead. Also I once got a heavenly lamb roast in this kitchen which was achieved by slow-roasting a large bit of frozen lamb until done. This seems to be a useful technique, especially in countries where freezing is the first thing that happens to meat exposed to the air. But I like my medium-high browned crisp chicken roast, for example.
Some traditional cooking techniques require long sessions of simmering. It is always advisable to test whether this is really necessary. For example, Amit, my source for my hummus recipe, advises cooking chickpeas for twelve hours to get them soft. If you cook them on top of the stove, this is good advice. My method of using a closed cast-iron roasting pot in the oven reduces the cooking time to a quarter or less.
Marcella Hazan (hard to avoid mentioning her) simmers her traditional Ragù, or Bolognese sauce, uncovered for a minimum of 3 1/2 to 4 hours (The Classic Italian Cookbook, p. 109-110). When I first made this sauce, I was still living in a student room in a green suburb of Haarlem (Holland), which was separated with a single sheet of chipwood from the living room of my landlords. After three hours, my landlady knocked and came in, sniffing.
“You seem to be cooking something…” — “Well, yes, in fact I’m trying out this recipe…” I told her about the recipe. “Four hours? This is madness! You are really one of these gourmets, aren’t you?” I sort of admitted an interest in food. “Such a superficial attitude!” She left me, shaking her head.
On that day my attitude was in fact more that of an experimenting scientist: I had tried the sauce every half hour or so, in order to make sure that Marcella’s cooking time made any sense at all. Amazingly, after 3 hours and thirty five minutes, the taste of the Ragù abruptly changed and mellowed in a clearly noticeable way. (It is things like these that make us believe blindly in Marcella’s expertise.)