If your bread isn’t completely stale, toast it. Preheat your oven to 175°C (350°F), place the bread cubes on a tray, and bake for 10–15 minutes until dry and lightly golden. Let cool.
Place sliced red onion in a bowl of cold water for 10 minutes. This softens their sharpness. Drain before using.
In a large bowl, toss the bread cubes with chopped tomatoes, drained onions, cucumber, and torn basil.
Drizzle with olive oil and red wine vinegar. Season with salt and pepper to taste. Toss gently until everything is evenly coated.
Cover and let the salad sit at room temperature for at least 30 minutes. This allows the bread to soak up the juices and flavors.
Taste and adjust seasoning if needed. Garnish with extra basil and a drizzle of olive oil before serving.
Notes
For extra flavor, rub a garlic clove on the bread before toasting or mixing.
Use the juiciest, ripest tomatoes you can find—they’re the heart of the dish.