Cook the cauliflower florets according to the package directions, typically by steaming or boiling until very tender.
Drain thoroughly in a colander, shaking to remove as much water as possible.
Transfer the hot, drained cauliflower to the bowl of a food processor or a high-powered blender.
Add the 3 tablespoons (45 ml / 1.5 fl oz) of butter and the heavy cream.
Pulse the mixture until it breaks down, then blend on high until it reaches a silky-smooth and creamy consistency. Scrape down the sides as needed.
Season generously with salt and pepper to your liking.
Transfer the hot caulimash to a serving bowl.
Top with an extra pat of butter and a crack of black pepper before serving immediately.