As a Brit living in the US, there are times when I'm asked to explain a particularly confusing aspect of my native culture. One of these is the age-old conundrum of what, exactly, is the difference between lunch, dinner, tea, and supper, and how and when the terms can be used interchangeably. The full answer requires a lot of hand-waving about geography, generational differences, and social class, but inevitably it will touch at some point upon the concept of a Sunday lunch, which is often a large family gathering involving a roast of some kind, of which the most important element, by far, is crackling.
We prepare the loin in approximately the same way that we get a turkey ready for Thanksgiving: We add a good, almost surprising amount of salt to the meat, and let it sit, uncovered, in the fridge for a couple of days. This allows the skin to dry and the salt to permeate through the meat (this is commonly referred to as a "dry brine," which plumps up the cells, adding moisture and flavor when the pork is roasted. Read more about it here). Brushing the skin with a little oil helps it to brown more evenly.
We start the oven very hot, which does most of the work to render the fat and crisp the skin. After half an hour, we reduce the temperature to finish cooking more gently. We aim to pull the pork out at 140°F (60°C), which takes about an hour longer, and after carryover cooking, it should be a rosy-pink medium. You can, of course, cook the roast more or less to your liking. You could also reverse-sear it, starting low and finishing hot, but with bones insulating one side and skin insulating the other, the benefits of the reverse-sear are not as obvious for a cut like this.
After resting, we carve it up and serve it, as is tradition, with Yorkshire puddings, a tart and spicy Apple Chutney (the recipe is included!) and a salad with spicy arugula, shaved red cabbage, and fresh apples.
Doesn't that crackling look lovely?
source: seriouseats