Cut the stem out of the cauliflower and break it up into smaller sections.
Bring cauliflower to a boil in a large pot of salted water. Boil until fork-tender, about 10 minutes.
Drain and transfer to a food processor.
Puree the cauliflower with the butter, garlic, salt, and pepper. Check taste and adjust.
Return to the heat if needed. Stir in and/or top with cheese.