Slice top off of garlic head. Drizzle with olive oil, sprinkle with sea salt and wrap in foil. Roast until soft and caramelized, about 35 minutes.
Place cauliflower and celery root in pot, cover with water, and add large pinch of salt. Bring to boil, reduce heat, and simmer until vegetables are tender, about 15 - 20 minutes.
Drain vegetables and add to food processor with a few cloves of roasted garlic, ghee, salt and pepper. Pulse until combined. Add more garlic to taste. Process to desired consistency.
Notes
For dairy-free: use coconut oil in place of gheeFor vegan: use coconut oil in place of ghee