Place the whole butternut squash and 2 tablespoons of water into the slow cooker. Put the lid on and cook for 7-9 hours on low. Heat olive oil in a medium pan on high. Cook onions and garlic until translucent, about 7 minutes. Set aside. After the squash is done remove it from the slow cooker, cut in half, remove the seeds and skin, and scoop out the flesh and place it back into the slow cooker. You can discard the seeds and skin. Pour the onion mixture and chicken broth in with the squash. Using a hand blender, blend the ingredients until blended and smooth. Cook on high for another hour. Add salt and pepper to taste. Serve with a sprinkle of parmesan cheese.

Tip: This soup can be made completely ahead of time and frozen into individual servings for easy dinners or lunches. Reheat on the stove or in microwave.