"Pan-roasting is hot and fierce. Slow-roasting is low and slow. One major advantage of slow-roasting is simplicity. Anything you can braise—short ribs, pork shoulder, lamb shoulder—you can slow-roast with a fraction of the effort. Unlike braising, you can skip the initial browning (which could take 20 minutes for a hefty cut, like brisket), you don't need a ton of aromatics to infuse the liquid, and you don't need a large volume of stock, or any wine, for that matter. Although slow-roasting essentially is a dry-heat method, it's gentle, and the finished succulent texture is similar to what you'd get with a braise. Meats become shreddable and moist, internal fats and collagen melted into tenderness. Slow-roasting coaxes tough-skinned winter squash into total submission (no peeling, no chopping), yields whole heads of cauliflower soft enough to eat with a spoon, gives whole chickens a rotisserie-esque texture, caramelizes and concentrates juicy things like fennel or sweet peppers, and is the most facile and impressive way to cook large fillets of fish."
Season peppers aggressively with kosher salt and pepper. 1 teaspoon of salt per pound is my standard measure. This can be done 1 to 2 days ahead; refrigerate, uncovered.
Preheat oven to 250°F. Place the peppers in a vessel that holds them snugly; they will shrink quite a bit while cooking, and too much empty space could lead to overbrowning, dryness, and a tough cleanup job. Add the ¼ cup water to the pot, which will throw off a little steam to start the cooking process.
Cover the pot, transfer to the oven, and go take a nap. Set an alarm for 1 hour.
Cook until the peppers are extremely tender but not dried out. If desired, continue cooking, uncovered, to brown surface, 20 to 30 minutes.
Serve this delectable-ness with lots of fresh lemon juice squeezed over, more salt and pepper for seasoning, and a drizzle of olive oil, unless there are plenty of pan juices lying about, in which case you should spoon those over.