Roast Leg of Lamb with Potatoes and Onions

Name: Roast Leg of Lamb with Potatoes and Onions
Ingredients: 1 6- to 7-pound bone-in leg of lamb, excess fat trimmed; 3 large garlic cloves, thinly sliced; 1 tablespoon extra-virgin olive oil; 1 tablespoon minced fresh thyme or 1 1/2 teaspoons dried; 2 teaspoons minced fresh savory or 1 teaspoon dried; 1 teaspoon minced fresh rosemary or 3/4 teaspoon dried; 1 teaspoon salt; 3 /4 teaspoon ground black pepper; 3 1/2 pounds russet potatoes, unpeeled, cut into 1/4-inch-thick rounds; 2 1/2 pounds onions, thinly sliced (about 8 cups); 1 3/4 cups beef stock or canned beef broth