Unwrap the pork and pat it dry with a paper towel. For best results, tie the pork with cooking string. This will ensure even cooking.
Place it inside a dish or a pan that is large enough to hold it comfortably and season with salt generously on all the sides. Pat the salt in rather than rub.
Cover the dish with plastic wrap to make sure it's air-tight and refrigerate for 18-24 hours.
Cooking Pork Loin:
Take pork out of the refrigerator about 30 minutes before cooking and leave it on the counter.
Take pork out onto the cutting board and evenly season it with Herbs de Provence, garlic powder, and pepper. (Remember, it's already salted.) Pat the seasoning in.
Dice shallots and apples and set them aside. Smash and mince garlic and set it aside as well.
Preheat the oven to 225° and move the oven rack to the middle of the oven so that closed Dutch oven fits well in the middle.
Preheat a large Dutch oven over medium-high heat for a few minutes.
Add oil and spread it evenly. Sear pork fat side down first for a few minutes, until there is a nice sear on it. Then turn and sear the sides, one at a time, until there is a nice brown sear on the as well. Take pork out onto a large plate and set aide whole searing the vegetables. (Don't sear the bottom of pork loin.)
Add a little more oil if needed and add onions and apples. Sauté for a few minutes, until start to get a golden sear on them.
Add minced garlic, stir, and sauté for few seconds, until it's fragrant.
Pour in chicken stock and add bay leaves and thyme.
Place pork loin over the vegetable mixture, fat cap up. If you have a leave-in thermometer, insert it into the center of the pork, towards the middle.
Cover the top with aluminum foil and then close the lid. Place it into the oven and let it cook until reaches 145° internal temperature.
Approximate time:For longer, thinner center cut - cook time will be about 20 minutes per lb. So a 4.5lb pork will take about 90 minutes.For shorter, thicker cuts - cook time will be about 30 minutes per lb. So a 4.5lb pork will take about 135 minutes.
When the pork reaches the temperature, take it out of the oven and out of the pot. Place it on a cutting board and tent with aluminum foil. Let it rest for about 15 minutes. If it was tied, make sure to take off the string before resting.
Gravy:
You'll be happy to know that the leftover vegetables and juices can be turned into the a delicious gravy.
Place the Dutch oven with everything leftover from cooking pork on the stove and heat it up over medium heat.
Sprinkle flour evenly over the top and stir.
Pour in chicken stock while slowly stirring. Make sure everything is mixed well and add the sugar, and some salt to taste.
Bring everything to simmer and stir and simmer until it's thickened.
Transfer the mixture into a blender or use an immersion blender to blend the it until smooth.