Preheat oven to 375 degrees.
Brown sausage in 12-inch nonstick skillet over medium heat, stirring frequently, 5 minutes. Add onion and cook, stirring occasionally, 5 minutes or until tender. Remove sausage and onion; set aside.
Stir in remaining ingredients except bread into same skillet; stir in bread.
Evenly spread bread mixture in 13 x 9-inch baking dish, then lightly press. Bake 30 minutes or until golden and heated through.