01 - Set the oven temperature to 400°F.
02 - Cut the top off the garlic bulb to expose cloves, drizzle with olive oil, wrap in foil, and roast for 30-35 minutes until soft and golden.
03 - Bring a large pot of salted water to a boil, add cauliflower florets, and cook for 10-12 minutes until very tender. Drain thoroughly and allow excess moisture to evaporate.
04 - Squeeze the roasted garlic cloves from their skins and place them in a food processor along with the drained cauliflower, butter, cream cheese, milk, kosher salt, and black pepper.
05 - Process the mixture until creamy and smooth, scraping down the sides as necessary. Taste and adjust seasoning accordingly.
06 - Transfer the mashed cauliflower to a serving dish, garnish with chopped chives if desired, and serve warm.