Preheat oven to 400°.
Remove crust from bread; cut bread into 3/4-inch cubes to measure 8 cups. Arrange bread cubes in a single layer on 2 jelly-roll pans. Bake at 400° for 10 minutes or until lightly toasted; cool. Place bread in a large bowl.
Reduce oven temperature to 350°.
Cook bacon in a large skillet over medium heat until crisp. Remove bacon from pan, reserving 1 tablespoon drippings in pan. Drain bacon on paper towels. Add onions to drippings in pan; cook 3 minutes or until soft, stirring often. Sprinkle sugar over onions; cook for 3 minutes or until onions begin to brown, stirring frequently. Add bacon and onion mixture to bread.
Return pan to heat. Coat pan with cooking spray. Add apple and celery to pan; cook 6 minutes or until lightly brown, stirring frequently. Stir in parsley and next 4 ingredients (through pepper); cook 1 minute. Add apple mixture to bread mixture; toss to combine.
Combine broth and eggs, stirring with a whisk. Add egg mixture to bread mixture; toss to coat. Spoon bread mixture into a 13 x 9-inch baking dish coated with cooking spray. Bake at 350° for 45 minutes or until browned.