Knead minced meat, egg, tomato paste and breadcrumbs, season well with salt and pepper. Form about 20 balls from the mixture and place them on a baking tray lined with baking paper. Cook in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 15 minutes. In the meantime, peel and finely dice the onion. Heat the oil in a pot and sauté the onion.
Deglaze with broth, stir in saffron and add rice. Cook for about 20 minutes at medium heat. In the meantime, quarter, clean, wash and cut the peppers into pieces. Rinse beans briefly with hot water and drain. Clean, wash and slice the celery (put some celery green aside). Clean, wash and slice tomatoes. Rinse the corn briefly and let it drain. After about 10 minutes, add vegetables to the rice and cook. Season soup with salt, pepper, lemon juice and 1 pinch of sugar.
Clean, wash and slice tomatoes. Rinse the corn briefly and let it drain. After about 10 minutes, add vegetables to the rice and cook. Season soup with salt, pepper, lemon juice and 1 pinch of sugar. Arrange soup in deep plates, add chopped balls. Serve garnished with celery green