Heat the oil in a pan and fry the finely chopped onions until light brown. Peel the celery, carrots, and garlic cloves and chop coarsely. Add to the onions and continue to cook while stirring constantly.
Cut the green pepper into halves, take away the seeds and wash carefully. Then cut into thin slices. Wash the tomato and cut into eight pieces. Chop the parsley. Add all the remaining ingredients to the onion mixture, season with salt, pepper and paprika.
Stir the tomato sauce into the beef stock and pour it over the vegetables. Mix in the rice and bring it to a boil. Then put the covered pot into a preheated oven at 400°F (205°C) and let it cook for 20 to 25 minutes until the rice is done.