Preheat oven to 450 degrees Fahrenheit. Bake the butternut squash on a baking sheet for 45 minutes to 1 hour, until you can easily slide a knife into the upper part of the squash. Remove from the oven and allow to cool for 20 minutes. Cut off the ends of the squash and pare away the skin. Cut the squash in half, removing the seeds. Dice the remaining flesh. Allow to cool completely. Bring a large pot of salted water to a boil and cook the pasta according to package instructions. In a saute pan large enough to accommodate all of the pasta, over medium-high heat, add the oil, mushrooms, butternut squash and salt and pepper to taste. Cook for several minutes until the mushrooms begin to soften. You may need to add more oil, as the mushrooms may absorb the liquid. Add the garlic and mix to combine until garlic begins to brown and the sides of the butternut squash become brown as well. If the pasta is not finished yet, remove the saute pan from the heat and wait until the pasta is done. When the pasta is done, return the pan to high heat, quickly add the spinach and deglaze with the white wine, which will help wilt the spinach lightly. Season with salt and black pepper. Quickly drain the pasta, add it to the pan and toss to combine the ingredients, mixing in most of the grated parmesan while you are tossing. Transfer to a serving dish. Top with more grated cheese and freshly ground black pepper. Serve at once!