Preheat oven to 450 degrees. Spray a medium casserole dish with cooking spray.
Place frozen broccoli florets in a medium bowl and microwave for 5-10 minutes, or until thawed, (or lightly steam fresh broccoli in a medium pot covered on medium low heat for about 5 minutes, or until tender), and lightly pat excess moisture out of the broccoli using a kitchen towel or paper towel.
In a large bowl mix together everything except for the topping ingredients, including broccoil. Stir until everything is well combined and pour into prepared casserole dish.
Mix ingredients for topping together in a small bowl and sprinkle evenly over casserole. Bake for 40-45 minutes, or until cheese is melted and lightly golden brown. Serve warm.