Is cauliflower steak marinaded in something or is it literally a sliced cauliflower
I think it's literally just a slice of cauliflower, although if you went to a restaurant where they made a bit of effort, you might get it marinaded and served with appropriate sides as part of a decent vegan or vegetarian meal.
M&S were ridiculed for their £2 slice of cauliflower earlier this year.
I suppose the logical thing to do with your cauliflower(s) would be to make a couple of steaks out of the middle and blitz the rest for cauliflower rice/cous cous, or put it in curry or a macaroni cheese (not sure if macaroni cheese with cauli, broccoli or other veg such as green beans baked into it has been mentioned yet.
Roasted cauliflower is indeed delicious and I think that the OP is now abundantly clear about the amount of normal food that just happens to be vegetarian there is available.
My favourites are:
halloumi/falafel/hummus/pitta/salad combos,
tortellini with pesto and grated courgette,
the macaroni cheese mentioned above,
spinach and ricotta caneloni,
pizza with peppers, onions, mushrooms and olives,
Spanish omelette and
paneer, chick pea and vegetable curry.
I'm not vegetarian and don't conciously cut down on meat although I've realised that I don't really like meals that are big pieces of meat with sides, or meat on pizza or with melted cheese in general, so if I eat meat, it's more likely to be something like paella or biriyani, that has small pieces of meat with rice and vegetables than steak and chips or chops and mash.