Cut the chicken breasts lengthways into two 1-1.5 cm slices each. Spread on a tray drizzled with olive oil or lined with aluminum foil. Brush each chicken slice with about 1 tablespoon of pesto. Place the thinly cut tomato slices on top and season with salt and pepper.
Cut the bread into small pieces, mix with the parmesan, crushed garlic and 1-2 tablespoons of olive oil. Spread on the chicken. Drizzle with a little olive oil if necessary and bake for 15 minutes.