Bring water to boil, add potatoes and parboil for 5 minutes. Strain. (Note: you want these to be a little underdone so that they wont get too mushy when you bake them in the oven).
In a large casserole dish, layer potato, tomato, mozzarella. While you will only have one layer, you'll want to overlap these so that the mozzarella melts over the potato and tomato. Sprinkle with Romano cheese, garlic, salt and pepper. Drizzle lightly with extra virgin olive oil.
Bake 20-25 minutes. Cheese will be melted and slightly golden. Serve hot.