Preheat your oven to 350°F (175°C).
Rinse the broccoli florets under cold water and chop them into bite-sized pieces.
Optional: Sauté chopped onions in a pan with a little oil over medium heat for about 5 minutes until translucent.
In a large mixing bowl, combine broccoli, French onion soup, cheddar cheese, sour cream, cooked rice, garlic powder, onion powder, black pepper, and salt. Stir until well combined.
Transfer the mixture into a greased 9x13-inch baking dish and spread it out evenly.
Bake for 25 minutes, then sprinkle French fried onions on top and bake for an additional 10 minutes until golden brown.
Let the casserole cool for about 5 minutes before serving.