Cook the potatoes in a saucepan of salted boiling water on the hob for 6–8 minutes until softened. Drain and transfer to a casserole dish.
Heat 2 tablespoons of the oil in a frying pan and fry the cauliflower and onion for 5 minutes until beginning to colour. Add to the casserole dish. Heat the remaining oil in the frying pan and add the garlic and spices. Heat gently for 30 seconds, then stir in the stock and tomatoes. Bring to the boil and add to the casserole dish. Cover with foil and place on the lower rack of the halogen oven.
Set the temperature to 200°C (392°F) and cook for about 45 minutes until the vegetables are tender. Check the seasoning, adding salt if needed, and serve with pilau rice.