Top and tail the fine green beans. Wash them and cut into slices around 5 cm (2 inches) long. Wash the celery stick and cut into small rounds.
Heat the oil in a saucepan and lightly brown the beans, celery, pepper and carrots for a few moments, stirring. Season.
Add the water, bring to the boil and add the rice and peas. Cover tightly and leave simmering for around 25 minutes.
Add the chopped mint leaves 5 minutes before the end of cooking. Grind in some pepper and sprinkle with grated Parmesan just before serving.