Tear the bread into 4cm pieces using your hands. In a large frying pan over high heat, heat 2 tablespoons of oil. Add half of the torn bread and cook for 5 minutes, turning occasionally until golden. Transfer the bread to a large heatproof bowl. Repeat with another 2 tablespoons of oil and the rest of the torn bread.
Combine the tomato, cucumber, basil, and green shallot with the bread, tossing gently until everything is mixed.
Combine the vinegar and remaining oil in a jug, taste, and season with salt and pepper. Drizzle the salad with the dressing, toss gently until well mixed, then transfer to a serving platter or bowl and serve right away.