Heat oven to 350°F. Spray 11x7-inch (2-quart) baking dish with cooking spray. In 6-inch skillet, heat olive oil over medium heat. Add bell pepper and green onions; cook 2 to 3 minutes, stirring occasionally, until bell pepper and onions start to soften. In large bowl, mix bell pepper mixture and all remaining ingredients except croutons. Spoon into baking dish. Top with croutons.
Bake 30 to 35 minutes or until hot and bubbly. If desired, sprinkle with additional sliced green onions.