Preheat oven to 350 degrees F .
In a large bowl, mix together mayonnaise, Parmesan cheese, garlic powder, and salt and pepper to taste.
Add broccoli florets, black beans, and cooked white rice to the bowl and stir until everything is evenly coated with the mayonnaise mixture.
Transfer the mixture to a 9x13 inch baking dish. Sprinkle shredded cheddar cheese over the top of the casserole.
Bake in preheated oven for 25 minutes or until cheese is melted and bubbly. Serve hot. Enjoy!.
