Goose Stew with Barley and Celery Root

Name: Goose Stew with Barley and Celery Root
Ingredients: 8 goose legs (2 to 3 pounds); 3 tablespoons duck fat, lard, or unsalted butter; Kosher salt and freshly ground pepper; 1 large yellow or white onion, sliced; 1 pound small mushrooms (such as yellow foot chanterelle or beech), halved or left whole; 2 teaspoons dried marjoram; 7 cups Basic Duck Stock or beef stock; 1 cup pearled barley; 1 cup peeled and sliced carrots; 1 celery root, peeled and cut into 1-inch cubes; 2 tablespoons chopped fresh dill; 4 to 6 tablespoons sour cream