Preheat the oven to 425°F then line a baking sheet with parchment paper or a silicone mat. Cut off the stem of the butternut squash then slice down the center lengthwise. Using a spoon, scoop out the seeds and loose flesh. Lightly rub with oil then place face down on the baking sheet. Roast for 30 to 45 minutes, until soft and golden brown. Set aside to cool.In a large pot, warm 2 tablespoons olive oil. Add the onion and cook for about 3 minutes, until translucent. Add the garlic, carrot, celery, salt & pepper and continue to cook for another 2 minutes. Lastly, add the pear, and dried sage. Cook for 5 to 10 minutes, until pear is soft.Once the squash is cool enough to handle, use a spoon to scrape the flesh into the large pot. There should be about 2 cups worth of squash. Add the broth, stir together then bring to a boil. Allow to cook for 5 minutes. Stir in vinegar then set aside to cool.While soup is still warm (but not boiling hot) transfer to a blender. Blend on high until smooth. Add more salt or seasonings, as desired. Pour into bowls, serve warm and enjoy!