1 3½ to 4-pound boneless pork top loin roast (single loin)
¼ teaspoon ground black pepper
2 small white and/or red onions, cut into wedges
2 medium carrots, cut into ½-inch-thick slices
2 stalks celery, cut into ½-inch-thick slices
½ cup bourbon
2 tablespoons tomato paste
4 cloves garlic, minced
2 cups reduced-sodium chicken broth
5 sprigs fresh thyme
½ of a sprig fresh rosemary
To prepare the stuffing: In a 3-quart saucepan, cook sausage in hot oil for 2 minutes. Add crawfish, the sliced onion, and the thinly sliced celery; cook until onion is tender. Remove from heat; add bread. Stir in enough of the water to moisten. Set aside.
Preheat oven to 325°F. Trim excess fat from pork roast. Butterfly the meat by making a lengthwise cut down center of meat, cutting to within ½ inch of the other side. Spread open. Place a knife in the "V" of the first cut. Cut horizontally to the cut surface and away from the first cut to within ½ inch of the other side of the meat. Repeat on opposite side of "V". Spread these sections open. Place pork open on a cutting board; cover with plastic wrap. Starting from the center, gently pound pork evenly until ½ inch thick (about a 15x9-inch rectangle).
Spoon stuffing in an even layer onto pork, leaving a 1-inch space on each long side. Starting from one of the long sides, roll pork into a spiral. Using 100 percent cotton string, tie the pork loin at even intervals until the whole pork loin is evenly shaped and tied. Sprinkle with pepper.
In a large roasting pan, combine onion wedges, carrot, and the sliced 2 stalks celery; place a rack over the vegetables. Place roast on top of rack (tuck vegetables under the roast). Insert an oven-safe meat thermometer into center of roast. Roast for 2 to 2- ½ hours or until thermometer registers 155°F.
Remove roast and vegetables from roasting pan, reserving drippings. Cover roast and let stand for 10 to 15 minutes. The temperature of the roast after standing should be 160°F.
Meanwhile, to prepare the sauce: Stir bourbon into reserved drippings in roasting pan, scraping to loosen browned bits. Transfer mixture to a medium saucepan. Stir in tomato paste and garlic. Bring to boiling; boil gently for 3 to 4 minutes or until mixture is thickened, stirring constantly.
Stir in chicken broth, thyme, and rosemary. Bring to boiling; reduce heat. Simmer, uncovered, for 10 minutes. Remove and discard thyme and rosemary sprigs. Cool slightly. Pour broth mixture into a food processor; cover and process until nearly smooth.
To serve, cut meat into ½- to ¾-inch-thick slices. Serve meat and vegetables with sauce.