In a medium bowl, place the tomatoes after slicing them in half. Then add all the marinade ingredients.
Chill for at least 2 hours, but not more than 24.
Just before ready to serve, soften butter and slather it onto both sides of each slice of bread. Use just enough on each slice to make the Parmesan stick.
Generously sprinkle Parmesan over a buttered slice of bread and put it in a skillet, cheese side down. While one side is cooking, sprinkle Parmesan over the other side. When the side that is cooking is nicely crusted, flip it over and cook the other side until both are a nice crusty brown.
Repeat with as many slices as you want to make.
Drape each slice with desired amount of the tomato mixture and then drizzle with extra marinade.