Begin by preheating your oven to 350°F (175°C) to ensure it's ready for baking.
In a large pot, bring water to a rolling boil. Carefully add the broccoli florets and blanch for 2-3 minutes, or until they are vibrant green and slightly tender. Drain thoroughly and set them aside to cool.
In a spacious mixing bowl, combine the cooked rice, 1 1/2 cups of the shredded cheddar cheese, milk, sour cream, mayonnaise, garlic powder, onion powder, black pepper, and salt. Stir all ingredients together until they form a smooth, cohesive mixture.
Gently fold the blanched broccoli into the cheese and rice mixture, ensuring that the florets are evenly dispersed throughout.
Grease a 9x13 inch baking dish with cooking spray or butter, and pour the broccoli-cheese mixture into it. Spread it out evenly with a spatula.
In a small bowl, combine the crushed buttery crackers with the melted butter, mixing until the crackers are well coated. Evenly distribute this buttery cracker topping over the surface of the casserole.
Finish by sprinkling the remaining 1/2 cup of shredded cheddar cheese on top, allowing it to melt beautifully during baking.
Place the casserole in the preheated oven and bake for 25-30 minutes, or until the edges are bubbling and the top has turned a golden brown.
Once done, carefully remove the casserole from the oven and let it rest for about 5 minutes to allow the flavors to settle before serving.
Notes
For an elegant touch, serve the casserole directly from the baking dish and garnish with freshly chopped parsley or chives.