Drain the tomatoes well in a sieve. Drain the mozzarella and cut into 8 slices. Heat the oil in a grill pan. Grill the aubergine slices in portions for 1-2 minutes, turning them over.
Place aubergine slices on a tray or plate. Cut tomatoes into 8 pieces. Cut the rind off the toast. Cover the toast with a slice of eggplant, tomato and mozzarella and season with salt, pepper and marjoram.
Place the toasts on a baking tray lined with baking paper and bake in a preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 5 minutes (until the mozzarella runs out and the toast is crisp).
Sprinkle each toast with 1 tsp. olive oil.