Carve tomatoes crosswise, blanch with boiling water, let stand briefly. Quench tomatoes, peel skin. Dice the flesh roughly. Peel and dice celery. Peel, wash and cut carrots into pieces.
Peel and finely dice the onion and garlic. Heat 3 tablespoons of oil in a large, wide saucepan. Add celery, carrots, 1 bay leaf, onion and garlic and fry for 2-3 minutes, turning. Add tomato paste and sauté briefly.
Add tomatoes and stock and simmer for about 10 minutes at medium heat. Meanwhile wash basil and shake dry. Pluck the leaves, except for a few for garnishing. Cut the rest finely. Wash the meat, dab dry and cut into about 48 pieces.
Wash and clean the peppers and cut them into about 36 pieces. Put paprika, bay leaf and chicken pieces alternately on 12 skewers. Heat 2-3 tablespoons of oil in portions in a large frying pan. Fry the skewers in portions for about 5 minutes while turning.
Season with salt and pepper. Puree the soup. Mix in basil and season to taste with salt, pepper, sugar and vinegar. Arrange soup on plates. Add mozzarella balls to the soup and garnish with remaining basil leaves.
Serve with skewers.