Preheat oven to 375 degrees F (190 degrees C). Move oven rack into the top third of the oven.
Heat the olive oil in a large skillet over medium heat, and spread the zucchini slices into the skillet in a single layer. If they don't fit, cook them in batches. Sprinkle pieces of garlic over the zucchini, and cook until the zucchini are golden brown on both sides, about 8 minutes per side. Remove from heat.
Arrange the slices of zucchini in an 9x12-inch glass baking dish, alternating with slices of mozzarella cheese and tomato, so that the slices overlap each other in a neat row pattern. Sprinkle the Parmesan cheese and basil over the dish, and season to taste with salt and pepper.
Bake in the preheated oven until the cheese is melted and brown and the dish is bubbling, about 30 minutes.
