Remove the leaves from the eggplants, and slice in half lengthwise. Carefully scoop out the centers of the eggplants, leaving a half-inch shell so they resemble ‘canoes’. Cut the center portion into small pieces, and set aside.
Preheat the oven to 350 degrees F (175 degrees C).
Heat the oil in a large skillet over medium heat. Add the onions and garlic, and saute for a few minutes, until tender. Add the eggplant pieces, and cook until soft, about 5 minutes. Then, stir in the tomato, green pepper, and parsley. Simmer for about 10 minutes.
Remove from the heat, and transfer to a large bowl. Stir in the bread crumbs until evenly blended. Divide the mixture evenly between the four eggplant shells. Sprinkle feta cheese over the top. Place the eggplant halves on a baking sheet.
Bake for 15 to 20 minutes in the preheated oven, until the tops are browned and the cheese is melted. Serve hot or cold. I prefer them chilled.