Slice bread and place pieces on a parchment paper-lined baking sheet. Use a clean cloth to brush bread with olive oil. Place in oven for about 4-8 minutes or until tops are slightly crispy. Take out and flip.
In a medium bowl, combine tomatoes, onions, olive oil, oregano, basil, and parsley.
Spoon the tomato mixture on each slice of bread, sprinkle with Parmesan cheese.
Bake in oven for 8-10 minutes or until bottom of bread is browned.