Cut the corn kernels off the cob. Collect the corn kernels in a bowl. Cut the corn cob into two halves (4 pieces in total). Keep them aside to add to the soup later.
Heat butter in a saucepan. Add garlic, celery, onion, and fry for 1 - 2 minutes to release the aroma of the ingredients and infuse their flavor into the butter.
Add diced potato, thyme, and corn kernels. Saute them for 5 - 6 minutes.
Add water, salt, and give the soup a good stir. Gently place the cob in the soup. Simmer the soup over low heat for 20 - 25 minutes. Discard the scum/foam floating on top of the soup gently using a ladle. Cover and simmer the soup over low heat for 15 - 20 minutes or till corn and potatoes are tender.
Transfer the soup to a blender or using an immersion blender grind it to a smooth consistency. If the soup is too hot to handle, wait for a few minutes. Using a sieve filter the blended soup, discard the corn pulp, and transfer back the creamy soup to the saucepan. Turn on the heat to the lowest setting.
Add cream. Season with salt, pepper according to taste, and stir to combine. Simmer the corn soup for 5 - 6 minutes. Turn off the heat.
Garnish corn soup with green onion, roasted corn, and cream.
Serve creamy corn soup warm with bread.