Grease a baking dish with olive oil. Preheat the oven to 428°F (220 °C). Wash the tomatoes, pat dry and chop with the mozzarella into 1/2″ (1 cm) thick slices.
Arrange a vertical layer of tomatoes, then mozzarella, etc. Clean and chop the onion and garlic. Salt the garlic and blend. Combine the olive oil, garlic, onion and white pepper and pour this mixture over the tomatoes and cheese.
Bake in the oven for 20 minutes. Sprinkle it with oregano and basil. Bake for another 5 min.