Preheat your oven to 350°F (175°C).

In a medium saucepan, bring water to a boil and add the broccoli. Cook for about 3-4 minutes until bright green, then drain and set aside.

In a large mixing bowl, combine the cooked rice, cooked broccoli, shredded cheese, cream of mushroom soup, milk, garlic powder, onion powder, salt, and pepper. Stir until well combined.

Grease your 9x13 inch baking dish lightly.

Pour the rice and broccoli mixture into the prepared baking dish and spread it out evenly.

Sprinkle breadcrumbs over the top if using.

Bake in the preheated oven for 30 minutes, or until the casserole is hot and the top is golden brown.

Let the casserole cool for a few minutes before serving.