Sauté bacon in a heavy large saucepan over medium heat until golden brown; set aside a few pieces to crumble as garnish.
Add onion, celery and garlic. Cover; cook until veggies are soft, stirring occasionally, about 7 minutes.
Add cauliflower, broth, and cheese; bring to a boil. Reduce heat to low, cover and simmer until cauliflower is tender, about 20 minutes.
Puree soup in batches in a blender.
Return to pan, add cream; let soup simmer. Thin with more broth if needed. Season with salt and pepper.
Ladle into bowls; top with cheese shavings, bacon, any fresh herbs (like tarragon), and a tiny drizzle of truffle oil – a little goes a long way.