Peel the onion and cut into fine cubes. Wash basil, shake dry, pluck leaves from the stems and chop. For the vinaigrette, mix vinegar, salt, pepper and honey.
Add 4 tablespoons of oil drop by drop. Stir half the basil into the vinaigrette. Sort the rocket, wash and shake dry. Wash the tomatoes and cut 4 pieces in half. Peel red onions and cut them into slices.
Cut 4 cheese balls in half. Knead minced meat, diced onion, remaining basil, 2 tablespoons breadcrumbs and egg. Season with salt and pepper. Form 8 mince balls and fill each with 1/2 tomato and 1/2 mozzarella ball.
Heat 2 tablespoons of oil. Fry meatballs all around for about 6 minutes. After 4 minutes add onion slices and the remaining tomatoes. Arrange rocket, onions, tomatoes, remaining mozzarella balls and halved meatballs in bowls.
Drizzle with vinaigrette. Roasted chiabatta slices taste good with it.