Combine tomatoes, shallots, garlic, basil, and 1 tablespoon olive oil in a small bowl. Refrigerate mixture while you prepare the baguette toasts and reduce the balsamic vinegar.
Preheat broiler. Slice baguette in ½ inch slices and place on a baking sheet. Drizzle olive oil over baguette slices. Place baking sheet under broiler and toast until the bread is golden. Remove from oven and let cool.
Place balsamic vinegar in small saucepan over medium heat and cook for 4-5 minutes. Remove from heat and let cool for a few minutes.
To assemble bruschetta, place toasted baguette slices on a serving tray. Top with tablespoon of tomato mixture and drizzle with reduced balsamic vinegar. Garnish with basil.