Heat the oil in a soup pot over medium heat.
Add the onions, celery, and bell pepper and sauté until the onion is soft and translucent, about 5 minutes.
Add the thyme, paprika, salt, pepper, turmeric, cayenne, and flour and stir well to combine.
Sauté 1-2 minutes until the herbs and spices are fragrant.
Add the sweet potatoes and broth and stir well to combine.
Increase the heat to bring to a boil, then decrease the heat to medium-low and simmer for 15 to 20 minutes until the sweet potatoes are tender and easily pierced with a fork.
Add the corn, milk, and nutritional yeast, stir well, and simmer another 1 to 2 minutes to heat through.
Serve hot garnished with sliced green onions and fresh chopped thyme.