Preheat oven to 400°F (200°C)
1. In a bowl, pour water over mushrooms and set aside to soak for 20 minutes. Drain, reserving ½ cup (125 mL) of the soaking liquid, and squeeze mushrooms dry. Set aside.
2. Meanwhile, in baking dish, combine rutabaga, carrots, parsnips and 1½ tbsp (22 mL) of the oil. Toss to coat well. Roast in preheated oven for 30 minutes. Add potatoes, onions, garlic, leek, sage, thyme and remaining 1½ tbsp (22 mL) of the oil. Toss to combine. Roast for 40 to 50 minutes or until vegetables are browned and tender (onions may be slightly charred). Remove dish from oven. Reduce oven temperature to 375°F (190°C).
3. Meanwhile, make Topping: Fill a large saucepan to the halfway point with cold water and add sweet potatoes. Bring to a boil over high heat. Cover, reduce heat and simmer for 20 minutes or until soft. Drain and rinse with cold water. Remove and discard skins. Return sweet potatoes to the pan. Using a potato masher, mash sweet potatoes. Beat in butter, yogurt, salt and nutmeg. Set aside.
4. Add reserved mushrooms, broccoli and peas to roasted vegetables in baking dish and stir to mix well.
5. In a small saucepan, mix cornstarch with ¼ cup (50 mL) of the tomato juice to make a smooth paste. Whisk in the remaining ¾ cup (175 mL) of tomato juice, red wine and reserved mushroom soaking liquid. Bring to a boil over medium heat. Reduce heat and simmer, stirring often, for 4 minutes or until sauce is thickened.
6. Pour sauce over roasted vegetables in baking dish. Stir to mix well. Spoon sweet potato topping over vegetables and smooth with a spatula.
7. Bake in preheated oven for 20 minutes or until topping is browned and vegetable mixture is bubbly around the edges. Let stand for 5 minutes before serving.
Omit cornstarch and replace tomato juice with 1 cup (250 mL) of tomato sauce and follow directions for sauce in Step 5.
For protein, add 2/3 cup (150 mL) shredded Swiss or Cheddar cheese or 1 cup (250 mL) cooked legumes or chopped nuts in Step 4.