1. Preheat oven to 350°F and grease a 9×13-inch baking dish.

2. Cook rice according to package instructions and let cool slightly.

3. Steam or blanch broccoli until bright green and tender, then drain.

4. In a saucepan over medium heat, melt butter and sauté onion until soft.

5. Add condensed soup and Cheez Wiz, whisking until smooth, then stir in garlic powder, pepper, and salt.

6. In a bowl, combine rice, broccoli, and cheese sauce, mixing gently to coat.

7. Pour mixture into prepared dish, sprinkle shredded cheddar on top, and bake uncovered for 25–30 minutes.

8. Let casserole rest 5–10 minutes before serving.