Do not cook the rice completely (firm to the bite) according to the instructions on the packet. Meanwhile, finely chop the celery and onion. Grate the carrots. Drain the rice and set it aside.
Cut the chicken into bite-sized strips and fry in oil in the pan. Then remove and set aside.
Fry the onion in the still hot pan until translucent. Add more oil if necessary. Steam the celery and carrots as well.
After 5 minutes, mix the rice and meat into the vegetables, pour the stock, salt, pepper and add lemon juice. Stir and let the rice swell for another 5 minutes.