Preheat oven to 275°F. Place tenderloin in a large braising dish. Season with salt and pepper; add thyme, bay leaves, and wine. Cover with lid or aluminum foil. Cook for three and a half hours, or until meat falls apart. When meat is almost finished cooking, reduce beef stock in a saucepan over medium heat until very thick, to about a half cup. Meanwhile, in separate pot over high heat, boil enough salted water to cover potatoes. Reduce heat to medium-high, and carefully add potatoes. Boil 15 minutes, or until fork tender. Remove from heat and drain. Pass potatoes through a ricer. Whip in butter, cream, and salt and pepper to taste. (Food processor may be used to purée potatoes, but take care not to overprocess or they will become gummy.) Remove meat from oven and shred using tongs. Pour reduced stock over pork and toss meat with tongs to evenly distribute. Set the oven to broil (400°F). In a deep casserole dish or loaf pan, arrange meat in an even layer. Top with puréed potatoes and smooth with a spatula. Sprinkle with shredded cheese. Place in oven for five minutes, or until cheese becomes golden brown.