Peel the Butternut Squash. Cut it in half and clean out the cavity containing the seeds. Cut the squash into 1-inch cubes. Prepares the potatoes, onion, carrots, celery, and garlic.
Heat a 4Qt Dutch oven or Soup pot on medium-high heat. Drizzle the heated pot with olive oil. Add in all of the chopped veggies, including garlic and celery. Cook for 5 minutes, stirring every minute.
Pour the chicken broth and water into the Dutch oven and sprinkle in the salt. Bring the soup to a boil, then turn down the heat to low.
Place the lid on the pot and simmer for 20 minutes. Make sure that the potatoes and squash are fork tender.
Use an immersion blender to carefully blend the soup until very smooth. Alternatively, you can let the soup cool down to room temperature and transfer to a high-powered blender.