Frozen cauliflower, steamed, makes excellent cauliflower mash (just whiz in the food processor after steaming, with a little butter, sour cream or coconut oil). Excellent substitute for mashed potatoes.
Blanching vegetables before freezing stops enzyme action which prevents them deteriorating. When I have more broccoli or cauli than I can use at once, I blanch and freeze the rest for later use.
Note to self: Make ice cubes every day, and dump out into container or similar, so I can make more. Keep this up for a large supply at the time of year when blanching and freezing vegetables - saves buying bags of ice from the supermarket!