Preheat the oven to 375 degrees. In a large bowl, toss the parsnips, carrots, potatoes and turnips, in 1 tablespoon of the olive oil, plus a little salt and pepper, until coated. Arrange the vegetables cut-side down on a large baking sheet and roast on the bottom shelf of the oven for 20 minutes or until the vegetables are beginning to brown. Turn the vegetables 2 or 3 times during cooking to prevent burning. In the same bowl, toss the pearl onions, garlic and portobello mushroom with 1 tablespoon of olive oil, plus a little salt and pepper, until coated. Add this mixture to the baking sheet of vegetables and gently stir to combine. Continue roasting for 7 to 10 minutes. Meanwhile, bring a small saucepan of salted water to boil and blanch the Brussels sprouts for 1 to 2 minutes. Drain thoroughly under cold running water. Set aside separately. In a small bowl, combine the shiitake mushrooms and the Brussels sprouts and toss with 1 tablespoon of olive oil, plus a little salt and pepper, until coated. Add them to the baking sheet of vegetables, stirring to combine. Dot the butter over the vegetables and sprinkle with 1/4 cup wine. Roast for another 7 to 10 minutes. Remove the vegetables from the oven and gently mix them with the thyme and parsley before serving.