Cut the cauliflower heads down into florets, then steam or boil for about 8-10 minutes, until completely fork tender and soft.
You can also cook the florets in an Instant Pot, by adding 1/2 cup of water to the bottom, and placing the cauliflower florets on the steamer insert. Using low pressure, steam for 8 minutes.
Let the cauliflower drain and cool, then squeeze in a kitchen towel to remove the majority of the water in the cauliflower. If you're in a hurry, I've had success with using tongs or rubber gloves to squeeze the cauliflower while it's still hot, just don't use your bare hands!
For a chunkier cauliflower mash, mix the cauliflower with the remaining ingredients by hand.
For a smoother texture, puree the squeezed cauliflower in a food processor with everything but the chives, for about one minutes, until smooth.
Mix in the chives if desired, or simply sprinkle on top to garnish. Enjoy!
*Weighing about 4 pounds in total, before trimming the stems.