Preheat oven to 250ºF.
Arrange the tomato slices on a baking sheet, drizzle them with EVOO and season with salt and ground black pepper.
Roast in the oven for an hour then turn it up to 300ºF for 30 minutes. Allow tomatoes to cool for a couple of minutes when they come out of the oven.
Layer a slice of tomato, a basil leaf then a slice of mozzarella on a serving platter, overlapping them like shingles. Repeat with the remaining ingredients.