Add the diced tomatoes to a large mixing bowl. Add the garlic, olive oil, and balsamic and gently stir to combine.
Season with salt to taste and top with chopped basil. Let sit to marinate while making the crostini.
Add additional olive oil as needed to a shallow bowl for dipping the crostini. Dip one side of each slice of bread into the oil then place olive-oil-side up on a baking sheet.
Broil until golden brown, about a minute.
To serve, arrange the crostini on a platter. Top each piece of bread with a spoonful of the tomato mixture. Finish with additional basil and serve.
Notes
Use ripe, firm tomatoes and drain any excess liquid before marinating to keep your bruschetta fresh and flavorful—not watery.