Preheat over to 425. Roast sweet potatoes with 1 T of oil. Roast, tossing once or twice, 15 to 20 minutes. Set aside.
Reserve 1 cup of corn kernels. Puree the rest in blender (about 2 minutes).
Heat remaining oil, cook celery and onion until softened, about 3 minutes. Add tomato paste and some thyme and cook another minute. Add broth, corn, a bay leaf and some salt and pepper.
2
While bringing soup to boil, peel potato, dice and add to soup. Cover the pot and simmer until potato is tender, about 25 to 35 minutes.
Remove bay leaf. Add reserve corn kernels