Preheat oven to 350.
Thinly slice (1/3-inch) the eggplant, rub lightly with oil, and arrange in a single layer on trays. Sprinkle with salt and pepper. Bake for 20-30 minutes, turning once, until golden brown and soft but not falling apart. (Alternatively, you can grill the slices – more flavorful but also much more hands on.)
Spread about half of the tomato sauce in the baking dish and increase the oven to 400.
Take a couple of T of ricotta and shape into a short tube. Set this at the end of a slice of eggplant and roll up. Place in baking dish and use a toothpick to keep it from unraveling. Repeat with remaining eggplant slices and filling, arranging the finished rolls in a single layer in the dish. Cover with aluminum foil and bake for 20 minutes.
To serve, spread a bit of sauce on each plate, top with 2 or 3 rollatini, remove the toothpicks, garnish with more sauce, and enjoy!