Preheat oven to 400°.
Score cut side of each eggplant half by making 4 crosswise cuts. Place the eggplant halves, cut sides down, on a foil-lined baking sheet coated with cooking spray. Bake at 400° for 25 minutes or until tender. Remove from oven; cool on pan 10 minutes. Carefully remove pulp, leaving a 1/3-inch-thick shell; reserve eggplant shells. Chop pulp.
Reduce oven temperature to 350°.
Place bread in a food processor; pulse 10 times or until coarse crumbs measure 1/2 cup. Drizzle the breadcrumbs with olive oil, and pulse to combine.
Heat a large nonstick skillet coated with cooking spray over medium-high heat. Add onion; sauté 3 minutes. Stir in the chopped eggplant, bell pepper, tomato, oregano, and garlic; cover, reduce heat, and simmer 10 minutes, stirring occasionally. Uncover and cook 5 minutes or until liquid evaporates, stirring occasionally. Remove from heat; stir in cheese, parsley, salt, and black pepper. Stuff each eggplant shell with about 1/2 cup onion mixture; sprinkle with breadcrumb mixture. Place on a baking sheet; bake at 350° for 30 minutes or until thoroughly heated and lightly browned.