Preheat the oven to 375°F (190°C). Cut the eggplants in half lengthwise and scoop out the flesh, leaving about 1/2 inch of the shell. Chop the scooped-out flesh and set aside.

In a skillet, heat olive oil over medium heat. Add diced onion and garlic, sauté until translucent.

Add ground beef and cook until browned. Stir in chopped eggplant flesh, bell pepper, tomato sauce, Italian seasoning, salt, and pepper. Cook for about 10 minutes until the mixture is heated through.

Fill each eggplant half with the meat mixture. Top with shredded mozzarella cheese.

Place the stuffed eggplants in a baking dish and cover with foil. Bake for 25 minutes, then remove the foil and bake for an additional 10 minutes until the cheese is bubbly and golden.