Arrange halved squashes flat-side-down on a lined baking sheet. Roast for 1 hour.
Remove insides of squash from peel, discarding seeds. Place roasted squash into a food processor and pulse until smooth.
In a large stock pot, stir together squash puree, broth, salt, pepper, and red pepper flake. Add roasted chicken, caramelized onion, and white beans. Simmer on low for 20 minutes.
Recipe by Rachel Schultz at https://rachelschultz.com/2016/04/06/butternut-squash-bisque/