Put the sweet potato and onion in a pot with about a cup of water, a sprinkle of salt, and bring to a low boil with the lid on. Let them cook for about 15 minutes, or until the sweet potato is pretty soft. Add the zucchini to the pot, stir it in, and leave it for another 5 minutes or longer if you want the zucchini to be really soft.
Puree the vegetables, along with the kale if you want to include it and maximize the nutrients in this soup. Add water as you need to (including the cooking water from the sweet potatoes) to get the consistency you want for your soup. You can use a hand blender, but a food processor or full blender is better if you're using the kale.
Season the soup with Indian spices like cumin, coriander and turmeric or your favorite mix, and a pinch of salt. Fresh ginger adds lots of flavor and nutrients. Enjoy your vegan sweet potato soup topped with some pumpkin seeds. I hope you enjoy the latest of my healthy vegan recipes.