Meal Prep Soup Base

Assemble cannellini beans, tomatoes, onions, carrots, spinach, celery, salt, bouquet garni, and bay leaves in a slow cooker. Pour in enough water to cover. Cook on Low or High until carrots are tender and flavors meld, at least 3 hours. Serve immediately or cool to room temperature. Ladle portions into reusable containers and refrigerate.