Preheat oven to 375F. Spray 13x9x2-inch baking dish with nonstick oil spray. Cut squash in half lengthwise and place squash cut side down in the lightly oiled dish. Bake until squash is tender, about 45 minutes.

Using a large spoon, scrape squash intoa food processor processor and throw the peel away. Add 1 1/2 cups broth to the processor bowl and puree until smooth. Transfer the squash puree to a large saucepan. Mix in milk slowly until it is as thin (or thick) as you like it. If you like your soup on the thinner side, you may want to add in even more than 1/2 cup of milk. Stir soup over medium heat until heated through. Season to taste with nutmeg, salt and pepper.