Preheat your panini grill or a grill pan over medium heat.
Place a little bit of mozzarella on top of one slice of bread. Add the tapenade to the top of the cheese followed by the tomato slices and a little more cheese. Place the other piece of bread on top and place into your panini pan (or grill pan). Cook for 5 minutes or until crispy and golden brown. Serve immediately. Enjoy!
Side Note: I always cook my paninis dry. I find that using oil or butter on the bread makes the sandwich too greasy. Try it - I bet you will like it and it's way better for you!