01 - Preheat the oven to 400°F.
02 - Slice the top off the head of garlic to expose the cloves. Drizzle with olive oil, wrap in foil, and roast for 30–35 minutes until soft and golden.
03 - Steam or boil the cauliflower florets until very tender, about 10–12 minutes. Drain well and let sit for 2 minutes for excess moisture to evaporate.
04 - Squeeze the roasted garlic cloves from their skins.
05 - In a food processor or using a hand blender, combine the cauliflower, roasted garlic, butter, milk or cream, salt, and pepper. Blend until completely smooth and creamy.
06 - Taste and adjust seasoning as needed.
07 - Transfer to a serving bowl, garnish with chives if desired, and serve hot.