Cut eggplants in half lengthwise and scoop out flesh, leaving a ½-inch shell. Chop the flesh into ¼ inch cubes, set aside.
In a large skillet, heat oil over medium-high heat. Add sausage, breaking it apart as you cook and stir until no longer pink. Add eggplant cubes and garlic. Cook and stir 1 minute more. Stir in ricotta, salt and pepper. Mix well.
Fill eggplant shells. Spread the sauce over bottom of lightly buttered 11 x 7-inch baking dish. Place eggplant over sauce and sprinkle tops with Parmesan cheese. Cover with foil and bake for 25 minutes. Remove foil and bake 10 minutes more.