01 - Preheat the oven to 400°F.
02 - Slice the top off the garlic bulb to expose the cloves. Drizzle with 1 tablespoon 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.
04 - In a food processor or large bowl, combine the hot cauliflower, roasted garlic cloves (squeezed from their skins), butter, milk, sour cream, salt, and pepper. Process or mash until completely smooth and creamy.
05 - Taste and adjust seasoning as needed.
06 - Spoon into a serving bowl, drizzle with remaining olive oil, and sprinkle with fresh chives.