Preheat your oven to 350°F (175°C).
Steam the broccoli florets until tender, about 5 minutes.
In a large bowl, combine the cooked rice, steamed broccoli, and shredded cheddar cheese.
Add the cream of mushroom soup and milk, mixing until well combined.
Season with garlic powder, black pepper, and salt.
Transfer the mixture to a greased casserole dish.
In a separate bowl, mix breadcrumbs with grated Parmesan cheese.
Sprinkle the breadcrumb mixture evenly over the casserole.
Bake in the preheated oven for 25-30 minutes until the top is golden brown.
Let it cool for a few minutes before serving.