Fill a large sauce pan with water. Bring it to a boil over high heat.
Remove the stalks and leaves from the cauliflower heads, leaving only the florets. Put the florets into the boiling water and boil until very tender, about 15 minutes.
Drain the florets and return to the empty pan or a mixing bowl. Use a hand mixer to blend up the cauliflower until smooth. You can also use a potato masher, or a food processor.
Add in the parmesan, olive oil and mix thoroughly. Garnish with chives. Serve hot.