Cut the ciabatta in half lengthways and toast in the oven until it just starts to brown. Take it out and cut the loaf into small cubes, about 1.5 cm wide, and place the cubes in a bowl.
Halve the cherry tomatoes (quarter large ones) and add to the bowl. Make sure you add any juice released while cutting the tomatoes to the bowl too.
Finely chop the spring onions and basil and add it to the bowl.
Drizzle liberally with olive oil and with balsamic vinegar. Season with salt and pepper and mix well.
Allow the salad to sit for at least four hours, stirring occasionally to see that the bread and tomatoes are starting to soak up the seasoning. The aim is to serve the salad before the bread goes soggy. Taste test before serving and add more olive oil, vinegar, salt and pepper as desired.
The panzanella tastes and looks best if you can get a variety of heirloom tomatoes in different colours. If you can't get cherry tomatoes, use normal tomatoes chopped into small pieces. Make sure you catch the juice and add it to the salad.