Preheat oven to 450 F. Place eggplant slices on baking sheet. Drizzle with EVOO. Season generously with salt. Bake at 450 F until browning, approx. 15-18 min. Remove from oven.
Top eggplant with mozzarella and tomato slices and basil leaves. Return to oven and bake until cheese melts, approx. 4-5 min.
Serve with oregano and red pepper flakes, as desired.