Cook rice covered with water at low heat for 30 minutes, then let it swell for another 10 minutes with the stove off. In the meantime, wash and clean the beans and break them into 3 cm long pieces. Peel and finely dice the onion. Clean and slice the mushrooms. Halve, seed, wash and finely dice the pepper. Heat oil in a pan.
Fry the onion, mushrooms and diced peppers in it. Add the beans, pour on the stock and stew everything for 12-15 minutes. Stir the rice into the vegetables, season with curry, salt and cayenne pepper and pour the mixture into an ovenproof dish. Spread cheese evenly on top. Bake the rice gratin in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas mark 2) for approx. 10 minutes