01 - Preheat oven to 350°F (175°C). Grease a 9×13-inch baking dish using butter.
02 - In a medium saucepan, bring water or broth to a boil. Add rice, cover, and reduce heat to a simmer for 15 minutes until tender and liquid is absorbed.
03 - Steam or blanch chopped broccoli florets for 2–3 minutes until bright green and just tender. Drain and set aside.
04 - In a large mixing bowl, combine cooked rice, blanched broccoli, diced onion, shredded cheddar cheese, milk, sour cream, condensed cream of mushroom soup, garlic powder, salt, and black pepper. Mix thoroughly until homogenous.
05 - Spread the prepared mixture evenly into the greased baking dish.
06 - In a small bowl, blend crushed Ritz crackers with melted butter until the crumbs are uniformly coated.
07 - Distribute cracker topping evenly over casserole. Bake for 30–35 minutes until bubbling and golden brown on top.
08 - Allow casserole to cool for 5 minutes before portioning and serving.