The variety is Romanesco, used in a lot of better restaurants for their wonderful slightly nutty flavour.
I've sliced them across very finely, raw, and tossed them into salads.
I've sliced them thinly lengthwise with a mandolin and chargrilled them, tossing them with some mint, garlic, vinegar and oil for an antipasto.
I've finely diced and braised them with some garlic, mint, Italian parsley, marjoram and finely-chopped lemon zest and spread them on chargrilled bread as a bruschetta.
The only downside to growing them is that you need space. Lots and lots of space.
Like at least this amount:
So dig up that waste of space of a lawn and plant these.