Put an oven rack in the center of the oven. Preheat the oven to 375 degrees F. Butter a 9 by 12-inch rimmed baking sheet. Set aside.
Arrange the tomato slices on the bottom of the baking sheet in a single layer. Drizzle with the balsamic vinegar. Lay the cheese slices on top in a single layer. Sprinkle with the garlic and basil and drizzle with olive oil. Season with salt and pepper, to taste. Arrange the bread slices on top and drizzle with olive oil. Bake for 25 minutes until the filling is bubbling and the bread is crisp and golden. Remove the pan from the oven and let cool for 5 minutes before serving.