Gather all ingredients. Preheat the oven to 325 degrees F (165 degrees C).
Roughly chop eggplant centers.
Heat olive oil in a large skillet over medium-high heat. Add chopped eggplant, onion, garlic, oregano, and black pepper: cook and stir until lightly browned.
Spoon mixture into hollowed-out eggplants.
Sprinkle each stuffed eggplant with Parmesan cheese, bread crumbs, and parsley. Place in a shallow baking dish. Cover with tomato sauce and mozzarella cheese.
Bake in the preheated oven until eggplant is fork-tender and cheese is bubbly, about 30 minutes.
Serve and enjoy!