Preheat oven to 400 degrees F (200 degrees C). Line a baking sheet with parchment paper.
Lay the 4 slices of Italian bread out on the prepared baking sheet; top each piece of bread with a tomato slice, a basil leaf, and a slice of mozzarella cheese.
Bake in the preheated oven until the cheese has melted, about 7 minutes.
Drizzle each sandwich with 1/2 tablespoon of olive oil and balsamic vinegar.
