Preheat the oven to 350°F. Cut half of a baguette into ½-inch slices and place on a baking sheet.
Chop tomatoes, onions, and garlic. In a bowl, mix these together with dried basil, olive oil, salt, and pepper. (To speed up the process, pulse these items in a small food processor until chopped)
Scoop some of the topping mixture onto each baguette slice. Cut more of the baguette if you have some left over.
Bake the bruschetta in the oven for 15 minutes.
Pour some balsamic vinegar on each slice to serve.