Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish and set aside.

Cook the rice according to package directions. For 2 cups of long-grain white rice, this typically means combining with 4 cups of water or broth, bringing to a boil, then reducing heat, covering, and simmering for 15-20 minutes until water is absorbed. Fluff with a fork and set aside.

Steam or blanch the broccoli florets until tender-crisp, about 3-5 minutes. You want them cooked but still slightly firm. Drain well and set aside.

In a large skillet or Dutch oven, melt 1/4 cup (4 tbsp) of butter over medium heat. Add the chopped onion and sauté for 3-5 minutes until softened and translucent.

Add the minced garlic and cook for another minute until fragrant, being careful not to burn it.

Stir in the cubed Velveeta cheese, condensed soup, and milk. Cook over medium-low heat, stirring frequently, until the Velveeta is completely melted and the sauce is smooth and creamy. Season with salt and black pepper to taste.

In a large mixing bowl, gently combine the cooked rice, steamed broccoli, and the prepared Velveeta cheese sauce until everything is evenly coated.

Pour the mixture into the greased 9x13 inch baking dish, spreading it out evenly.

For the optional topping: In a small bowl, combine the panko breadcrumbs with 2 tablespoons of melted butter. Sprinkle this mixture evenly over the top of the casserole.

Bake for 20-25 minutes, or until the casserole is hot and bubbly, and the topping (if used) is golden brown. Remove from oven and let stand for 5 minutes before serving.