Beef Barley Soup

INGREDIENTS

• 3 lb. meaty beef or veal shanks
• 3 large yellow onions, chopped
• 6 carrots, peeled and chopped
• 4 celery stalks, chopped
• 1 cup tomato puree
• 1 cup barley
• 6 Tbs. (3/4 stick) unsalted butter
• 1 lb. fresh cremini mushrooms, brushed clean and sliced
• 1/2 tsp. minced garlic
• Salt and freshly ground pepper, to taste
• 4 Tbs. chopped fresh dill
• 1/4 cup chopped fresh flat-leaf parsley
• 6 Tbs. sour cream (optional)