2 lb dry bread, as dry as possible, in 1 inch cubes. Can add a little pumpernickel or rye, but not too much.
8 oz. sausage (best quality possible)
1 c. onion, small diced
3/4 c. celery, small diced
1 c. mushrooms, sliced (optional)
1/2 tbsp sage, dried
1 tsp fresh thyme
fresh rosemary (not dried), optional
2-3 c. chicken stock (ideally organic. well, ideally homemade.)

Cook sausage, break into small pieces, remove from pan. Cook vegetables in remaining rendered fat. Add seasonings, cook 3 more minutes. Add to bread cubes. Add a little stock, mix completely, check consistency, and keep adding stock in small amounts until achieving desired consistency. Season to taste with salt and pepper. Put in buttered baking dish, pressing into edges. Cover with foil, bake at 350 for 20-30 minutes. (if you want a crust, remove foil for the last 5-10 minutes)

Source: Thanksgiving Dinner class, PA Culinary Institute, Chef Don Hutchins, 11/12/06