Halve and core the tomatoes. Then cut into cubes. Cut the spring onions into rings. Press the garlic. Mix everything together with salt, pepper, sugar and olive oil. Finally, add the basil leaves, torn into pieces, to the bruschetta, depending on your taste. Briefly grill the chiabatta slices in the oven so that they become crisp. Put plenty of tomato mixture on the Chiabatta and drizzle with a little olive oil again on a plate.