Preheat the oven to 450°F. Line a large rimmed baking sheet with parchment paper.
In a large bowl, combine tomatoes, garlic, basil, red onions, olive oil, balsamic vinegar, salt and pepper; set aside.
Use a bread knife to slice the baguette diagonally into 1/2-inch thick slices (about 24 slices). Place on the prepared baking sheet and bake for 5-7 minutes, watching closely to not let them burn. Immediately rub the garlic on the bread slices when they come out of the oven.
Add the tomato mixture on top if serving immediately, or serve on the side. Top with freshly grated parmesan cheese, if desired.
Storage: Store any leftovers in an airtight container. They will last about 4-5 days in the fridge. It's best though to keep the three ingredients separated. Do not assemble until ready to serve/eat.
Substitutes: For best results, follow the recipe as is. However this is a very versatile recipe, so feel free to change type of tomatoes and bread.
Nutritional Data: Please note that the nutrition label provided is an estimate based on an online nutrition calculator. It will vary based on the specific ingredients you use.
Calories: 87kcal | Carbohydrates: 12g | Protein: 2g | Fat: 3g | Saturated Fat: 1g | Sodium: 227mg | Potassium: 100mg | Fiber: 1g | Sugar: 1g | Vitamin A: 285IU | Vitamin C: 5mg | Calcium: 22mg | Iron: 1mg