In a mixing bowl, combine the diced tomatoes, chopped basil, minced garlic, olive oil, balsamic vinegar (if using), salt, and pepper. Mix well and set aside to marinate for about 10 minutes.

Preheat the oven to 400°F (200°C). Place the sliced bread on a baking sheet and toast in the oven for about 5-7 minutes or until golden brown.

Remove the toasted bread from the oven and top each slice generously with the tomato mixture. Serve immediately.