Heat oil in a skillet over medium heat, add cauliflower and cook, stirring occassionally for 10-12 minutes. Add the garlic, cover the pan and continue to cook 2-3 more minutes, or until cauliflower is completely tender.
Transfer the cauliflower to a food processor and blend until smooth. Scrape down the sides and add the Parmesan, cream cheese, salt, and black pepper. Continue to blend until smooth, adding the warm milk to thin, if needed. Transfer to a serving bowl, garnish with butter and serve.