Preheat the oven to 200ºC/400ºF/gas mark 6.
Rinse the cauliflower and then toss it around in the lemon juice. Place the florets in a roasting tray and sprinkle with the curry powder.
Peel and chop each onion into six, (individual slices will burn). Add the onion to the cauliflower and pour over the olive oil.
Roast in the oven for about 30 minutes, turning everything once until nicely golden and beginning to caramelise.
Add the butter beans, cider vinegar and butter/margarine to the vegetable pan, place it back in the oven but switch off the heat, the idea is to heat through rather than cook the beans.
Whilst the vegetables are roasting rinse the rice, place it in a pan, (ideally the base of a tiered steamer), of cold water with a pinch or salt, bring up to a boil and then cover and simmer until tender. Drain.
Now steam your spinach. I just place mine in a steamer over the rice, but you may prefer to use a separate pan. Steam the spinach until it just collapses and drain (there is no need to squeeze it here as it should remain really juicy).
Add the rice and spinach to the vegetable pan and season well. Add more vinegar, chilli, or salt to taste.
Serve with a spoonful of plant-based yoghurt and a sprinkling of mint.