Preheat your oven to 400°F (200°C).
Arrange the sliced baguette on a baking sheet and brush each piece lightly with olive oil.
Toast the baguette slices in the oven for about 5-7 minutes or until they are golden brown and crispy.
In a mixing bowl, combine the diced tomatoes, chopped basil, minced garlic, balsamic vinegar, and the remaining olive oil. Season with salt and pepper to taste.
Remove the toasted baguette from the oven and let it cool slightly.
Spoon the tomato mixture generously onto each toasted baguette slice. If desired, sprinkle shredded mozzarella cheese on top.
Return the bruschetta to the oven for an additional 2-3 minutes to melt the cheese, if using.
Serve immediately while warm.