How to Make It
Make 20 small incisions all over the fatty side of the pork roast. Insert a slice of garlic in each slit. Season the meat all over with 2 tablespoons of the thyme leaves, 1 1/2 tablespoons of salt and 1 tablespoon of ground pepper. Cover and refrigerate overnight.
Preheat the oven to 400°. Coat the bottom of a very large roasting pan with the olive oil. Set the pork roast in the pan, fat side up, and surround it with the onion wedges. Roast the pork for 45 minutes. Add the pear wedges to the pan, turning them to coat with the drippings. Continue roasting the pork for 20 to 30 minutes longer, or until an instant-read thermometer inserted in the thickest part of the meat registers 150°. Set the pork on a large platter and surround it with the roasted pears and onions. Cover with foil.
Meanwhile, in a large saucepan, combine the pear cider, thyme sprigs, cinnamon stick, peppercorns and clove. Boil over high heat until reduced to 2 1/2 cups, about 30 minutes.
Discard the fat from the roasting pan and set the pan over moderate heat. Add the shallots and cook, stirring, until wilted, about 3 minutes. Add the reduced pear cider and bring to a boil, scraping up any browned bits. Transfer the sauce to a small saucepan and simmer over moderate heat until reduced to 1 cup, about 8 minutes. Strain the sauce and add the remaining 1/2 teaspoon of thyme leaves. Season with salt and pepper.
Carve the meat and arrange the chops on a platter. Arrange the roasted pears and onions and the cherry tomatoes around the pork and serve with the pear-cider sauce.