Preheat oven 350 to degrees. Quarter the potatoes, and blanch until just tender. Grill the slab bacon and pork sausages (this can be done in the oven).
In a small pan sauté garlic, onions, potatoes, and mushrooms. Place the sausages, bacon, and vegetable mixture in a roasting pan or a casserole dish add the broth and Guinness stout and bring to a simmer. Cover and bake 1 hour in conventional oven finish with thyme, salt, pepper, and butter. Serve as a stew with Irish soda bread.