Heat oven to 375ºF and roast squash for 10 minutes. (I do this because it makes it MUCH easier to cut - and it adds some flavor. You can definitely skip it if you prefer.)In a large soup pot, melt butter. Sauté sliced onion until soft and fragrant, about 5-8 minutes. Crush garlic with your knife and then loosely chop. (It will be blended later.) Add garlic, salt, pepper, and sage, and sauté over low heat for another 30 seconds.Remove squash from oven and cut into chunks. (You can choose to remove the skin, but it is totally edible, so I leave it on!) Add squash to soup pot and cover with 2 cups broth. Stir to combine and simmer for 10 minutes. Squash will be very soft. Remove from heat and add to blender. Blend until smooth and return to stove.Add 1 cup milk and bring to a low simmer. Simmer for 5 minutes, stirring occasionally, or until desired thickness is reached.Ladle into bowls, and top with freshly ground black pepper, and if desired, parsley and parmesan cheese. Serve with Whole Wheat Naan!