Fill up a large (6-quart) stock pot with an inch or two of water. Place a steamer insert in the pot, cover with a lid, and put the pot on a burner set on high.
While waiting for the water to boil, wash and trim the cauliflower. Cut up the florets and stem. Slice up all the garlic cloves. (Don't worry about how everything looks -- it'll all get pulverized later in the food processor.)
Once the water in the pot is boiling, throw in the stems, half of the florets, and all of the garlic. Salt everything liberally.
Then, put in the rest of the cauliflower, season with more salt, replace the lid, and steam everything until soft (~10 minutes).
Drain everything into a colander, and then dump it all into food processor fitted with the steel knife attachment. Season with some fresh cracked pepper and microplaned nutmeg. Add the butter.
Process everything until smooth. Season to taste. These faux “mashed potatoes” reheat beautifully in the microwave.