Thinly slice a baguette; arrange in a single layer on a baking sheet. Brush with olive oil and sprinkle with salt. Bake at 425 degrees F until lightly golden, about 7 minutes. Let cool slightly.
Slice 1 Japanese eggplant into 1/2-inch-thick rounds and toss with olive oil, salt and pepper. Spread on a baking sheet and roast about 12 minutes at 425 degrees F. Top the toast rounds with sliced mozzarella, the roasted eggplant and some marinara sauce; sprinkle with parmesan. Bake until the cheese melts.