For a richer flavor, toast the spices in a dry pan for a minute or two before adding them to the pot. Adjust the amount of curry powder to your preferred level of spiciness. If you don't have an immersion blender, you can carefully transfer the soup to a regular blender in batches, being cautious of the hot liquid. Return the blended soup to the pot after blending. This soup freezes well. Allow it to cool completely before transferring it to freezer-safe containers. Feel free to add other vegetables to the soup, such as carrots, celery, or spinach. Add heartier vegetables along with the potatoes, and leafy greens towards the end of the cooking time.