Peel and slice turnips, carrots, parsnips and kohlrabi into 1/4-in. julienne strips. Place in a 13-in. x 9-in. baking pan coated with cooking spray. Sprinkle with parsley, pepper and tarragon. Pour broth over all. Top with onions and garlic. Cover and bake at 350° for 1 hour or until vegetables are crisp-tender. Uncover; bake 10-15 minutes longer or until vegetables reach desired tenderness.