Roasted Vegetable Soup
["1 lb. carrots, cut into 1 1/2-inch pieces", "1 lb. potatoes, peeled and quartered", "1/2 lb. parsnips, cut into 1 1/2-inch pieces", "2 large onions, cut into eighths", "6 cloves garlic, unpeeled", "1 Tbsp. olive oil", "1/2 tsp. salt", "1/4 tsp. pepper", "2 (13 3/4 oz. each) cans chicken broth, divided", "1/2 tsp. dried thyme, crumbled", "2 c. milk", "2 Tbsp. fresh chopped parsley", "fresh herb sprigs for garnish (optional)"]
["Heat oven to 500\u00b0.", "Place carrots, potatoes, parsnips, onions and garlic in medium roasting pan.", "Sprinkle with oil, salt and pepper and toss to coat vegetables evenly; arrange vegetables in a single layer.", "Place pan in oven and immediately lower oven temperature to 350\u00b0.", "Roast vegetable, uncovered, for about 1 hour and 40 minutes, stirring several times, until tender and lightly browned."]
["carrots", "potatoes", "parsnips", "onions", "garlic", "olive oil", "salt", "pepper", "chicken broth", "thyme", "milk", "parsley", "fresh herb sprigs"]