Cut 1/2 in. off the top of each onion; trim bottom so onion sits flat. Scoop out center, leaving a 1/2-in. shell. Chop remaining onion, set 1/2 cup aside (discarding remaining onion or save for another use). Place onion shells in a Dutch oven or large saucepan and cover with water. Bring to a boil; reduce heat and cook for 8-10 minutes.
Meanwhile, in a large skillet, cook bacon over medium heat until crisp. Remove to paper towels; drain, reserving 1 teaspoon drippings. In same skillet, saute the chopped onion, carrots and red pepper in dripping for 8 minutes or until tender. Remove from the heat; stir in the bread crumbs, parsley, butter, salt, pepper and bacon.
Drain onion shells; fill each with about 1/3 cup vegetable mixture. Place in an ungreased shallow 3-qt. baking dish. Pour broth over onions. Cover and bake at 350 degrees F for 45-50 minutes or until heated through.