Potato soup? Not quite! But even without the potatoes, this soup is just as tasty!
Cook the bacon in a Dutch oven over medium-high, frequently stirring, until bacon is crisp, about 10 minutes. Transfer bacon to a paper-towel-lined plate to drain.
Add onion and celery to bacon drippings over medium-high. Cook while constantly stirring until the veggies have softened, about 5 minutes. Add cauliflower, salt, and pepper; cook, and continue stirring for 2 minutes. Add chicken stock, and boil. Turn the heat down to medium. Cover and cook until the cauliflower becomes tender, 10 to 15 minutes. Uncover and simmer 10 minutes.
Transfer soup to a blender. Remove center piece of blender lid (this'll let the steam escape); secure lid on the blender, and place a clean towel over opening in lid. Process for 30 seconds or until it's at your desired consistency. Return soup to a Dutch oven over medium-low. Stir in cream, and bring to a low simmer. Stir in 1 cup of the cheese until it melts, then remove from heat. Top each serving with sour cream, scallions, cooked bacon, and remaining cheese.