Beef And Barley Stew With Mushrooms

Name: Beef And Barley Stew With Mushrooms
Ingredients: 2 Tbsp unsalted butter; 2-3 pounds beef chuck, cut into chunks; Salt; 3 cups chopped onions; 1 pound button or cremini mushrooms, quartered if small or 1/4-inch sliced; 1 quart beef or chicken broth; 3 cups water; 2 teaspoons dried marjoram; 1 cup pearl barley; 1 cup roughly chopped carrot; 3 cups celery root, peeled and chopped into 3/4-inch to 1-inch chunks; Black pepper; About 1/2 cup sour cream (around 1 Tbsp sour cream per serving); Dill for garnish