Wash the tomatoes and dab them dry. Cut mozzarella into cubes (1.5 x 1.5 cm). Wash basil, dab dry and pluck leaves from the stalks. Cut about half into fine strips. Wash and clean spring onion and cut into fine rings. Season vinegar and 3 tablespoons of water with salt and pepper, fold in oil.
Add spring onion and basil. Put the mozzarella cubes, basil leaves and cherry tomatoes alternately on the skewers. Place the skewers in a well sealed tin. Fill basil vinaigrette into an extra jar. To eat, sprinkle the vinaigrette on the skewers