Place soup, milk, salt, pepper and onion in oversized mixing bowl and mix well. Stir in cheese.
Microwave broccoli cuts in a 1 1/2-2 qt. covered baking dish for approx. 5 minutes, stir and microwave 5 minutes more. Drain and add to soup mixture. Mix well.
Rinse out and dry broccoli microwave dish, spray with non-stick spray and pour mixture into bowl. Place on foil-lined cookie sheet and bake uncovered in preheated oven at 375°F for approx. 25 minutes or until heated through.