Place all ingredients except the vegetable broth into a large plastic food storage bag. Seal the bag well and place in the freezer. When it comes time to cook, thaw overnight in the refrigerator, and empty the contents of the bag into a 6-quart slow cooker. Add the vegetable broth.
Cover and cook on low for 8-10 hours, or on high for about 6 hours. Use a handheld immersion blender and pulse a few times to mash up the squash and naturally thicken the broth. Season to taste with a bit more apple cider vinegar, salt, and pepper, if desired.