In a small bowl, mix together the salt, black pepper and brown sugar. Arrange the turkey in a large (9x13”) baking dish, pat the tops dry, and season on both sides with the salt mixture. Let sit in the fridge for at least an hour or up to 24 hours (24 hours will give you better texture and deeper flavor).
Preheat the oven to 275°F.
Drain any liquid that’s come off the turkey, and pat dry a little. Scatter garlic, shallots, and nestle herbs around the turkey. Pour the olive oil all over to cover. Season the oil with salt and pepper (just like your pasta water should be seasoned, so should the fat you cook in), and cover tightly with foil or a tight fitting lid.
Place in the oven, and bake for three hours (at this point your turkey will be cooked through and mostly tender). Remove foil/lid, use a spoon to baste some of the fat on top of the exposed parts of the turkey, and bake again until the skin is a deep golden brown, about 45–60 more minutes.
Remove from the oven, and let cool slightly. To serve, of course you don’t need to do any carving—the bones will slip right out, and the meat should effortlessly shred, not unlike slow-cooked pork or short ribs. You can just serve it straight from the baking dish or arrange the turkey on a platter and spoon a little of the fat and the hunks of caramelized garlic/shallot all over.