This is a simple way to cook a beautiful, flavorful holiday roast. I like to finish my pork loin with chermoula, a North African-inspired vinaigrette that's just a bit lighter than the usual pan gravy.
Preheat oven to 325 degrees F. For the pork loin: Season generously with salt on all sides. Roughly chop thyme, rosemary leaves, sage, and garlic together so that they're combined. Set aside. Truss the pork loin for even cooking: Take five feet of butcher's twine; tie the twine around one end of the loin with a square knot, leaving the twine long on one end. Pass the twine under the loin about a half-inch down and bring it all the way around; tuck and tighten the string, closing the loop. Repeat until the entire pork loin is trussed. At the end, tie the two loose ends of the string together. Rub the herb/garlic mixture all over the pork.
Slowly heat a shallow roasting pan over low heat. When pan is preheated, add 2 tablespoons olive oil and raise heat to medium. When the oil is hot and shimmering, add the pork loin, fat side down, and roll it around to sear on all sides, 1-2 minutes per side. Add more oil as necessary. Place in the oven for 40 minutes, until a thermometer registers about 138 F in the thickest part of the meat.
For the chermoula vinaigrette: Heat a dry pan over medium-high heat and add the peppercorn, coriander, cumin, and fennel seed. Toast the spices, shaking the pan to avoid burning, about 2 minutes. When the spices are fragrant, remove from heat and place in a food processor along with sumac, Aleppo pepper, lemon zest and juice, salt, and olive oil. Pulse to combine; consistency should be loose but still a bit crunchy with spices. Set aside.
Check pork after 40 minutes to see that it registers about 138 degrees F; increase oven temperature to 425 F. Place the pork back in the oven and cook another 5 minutes.
Pork is done when a thermometer registers 145 degrees F (the temperature will continue to rise to about 150 F as it rests). Meanwhile, finish the chermoula by coarsely chopping cilantro and parsley and adding it to the vinaigrette. Pour the pan drippings from the pork into the vinaigrette and stir to combine. After the pork has rested and come to temperature, cut the twine off and slice. Serve with chermoula vinaigrette on top.