This sweet and hearty vegetarian soup is supremely satisfying on a chilly fall day.
1 medium butternut squash
6 sprig fresh thyme
4 sprig fresh sage
2 tbsp. small sage leaves
¼ tsp. cayenne pepper
¼ tsp. ground cinnamon
Kosher salt and pepper
1 large onion
2 medium carrots
1 stalk celery
1 tsp. olive oil
¼ tsp. paprika
1. Peel the squash. Cut 1/2 inch off the bottom and top and discard. Cut the squash in half, scoop out the seeds and reserve in a small bowl. Cut the squash into 2-inch pieces. Using kitchen twine, tie the thyme and sage sprigs together.
2. In a 5- to 6-quart slow cooker, whisk together the cayenne, 1/4 teaspoon cinnamon, 5 cups water, and 1/2 teaspoon each salt and pepper. Add the squash, herbs, onion, carrots, and celery and mix to combine. Cook, covered, until the vegetables are very tender, 6 to 7 hours on low or 4 to 5 hours on high.
3. Meanwhile, rinse the squash seeds, removing any pulp. Place them on a paper towel and let dry until ready to use.
4. Ten minutes before serving, heat the oil in a small skillet over medium heat. Add the seeds and cook, tossing, for 3 minutes. Sprinkle with the paprika and a pinch cinnamon. Add the sage leaves to the skillet and cook, tossing, until the seeds are toasted, about 2 minutes.
5. Remove the herbs from the soup. Using a handheld immersion blender (or a standard blender in batches), purée the soup. Ladle the soup into bowls and top with the spiced seeds and sage. Dollop with sour cream, if desired.
Make Ahead: Freeze the soup for up to 3 months. Thaw in the refrigerator overnight. Reheat in a large saucepan, covered, over medium heat, about 10 minutes.