I heard that you can make "mashed potatoes" without potatoes, instead, use cauliflower.
Never tried that. But, if the cauliflower gets really, really soft, it does lose its firmness and I can see how it might become more like "mashed." Then if you cream it, perhaps it could be closer to mashed.
Might try it, but, I simply enjoy eating steamed cauliflower.
Chrissy