For the best texture, tear the bread into pieces and let it dry on a large baking sheet for a few hours or overnight. Preheat the oven, toss the bread with a little good olive oil, spread it on baking sheet and bake it at 200 C (400°F) for 10 to 15 minutes. Aim for crispy edges while keeping the center chewy.
Slice and salt them, then let the tomatoes sit for about 15 minutes. This process draws out their juices, intensifies their flavor, and provides delicious liquid for the dressing. Meanwhile, you can toast your bread while the tomatoes rest in the colander.
In the same large bowl with the tomato juice, combine 1/4 cup red wine vinegar, 1/2 cup high-quality extra virgin olive oil, 1 to 2 minced cloves of fresh garlic, fresh thyme, and a squeeze of Dijon mustard. Season with salt and pepper and whisk everything together to combine.
Add the tomatoes, red onion, fresh basil leaves, mozzarella and toasted bread to the bowl with the dressing. Toss to combine. Allow the salad sit for at least 30 minutes before serving to ensure the flavors meld into the bread. Serve chilled or room temperature.