Arrange broccoli in a vegetable steamer over boiling water. Cover and steam 3 minutes or until crisp-tender. Set aside.
Place bread cubes in a 1-quart casserole coated with cooking spray; sprinkle with cheese. Top with broccoli, carrot, red pepper, and green onions. Combine milk and remaining ingredients in a small bowl, stirring well; pour over broccoli mixture. Cover and chill 8 hours.
Remove from refrigerator, and let stand, covered, at room temperature 30 minutes. Bake, uncovered, at 350° for 40 minutes or until set. Let stand 10 minutes before serving.