Preheat oven to 400°F. In a large mixing bowl, whisk together the olive oil, balsamic vinegar, kosher salt, and black pepper. Add diced tomatoes, basil, and garlic to the bowl. Toss to coat, allowing the mixture to marinate while you prepare the bread.
2 tablespoons extra-virgin olive oil, 1 tablespoon balsamic vinegar, ½ teaspoon kosher salt, ¼ teaspoon black pepper, 4 globe or plum tomatoes, ¼ cup fresh basil, 2 cloves garlic