Place the casserole, uncovered, in the preheated oven and bake for 15–20 minutes, or until the cheese on top is fully melted, the edges are bubbling, and the center is steaming hot. The surface should look glossy and the broccoli just tender.
Remove the casserole from the oven and let it rest for 5 minutes so it thickens slightly and holds together when scooped. Serve warm, straight from the glass dish, making sure each spoonful has plenty of broccoli, rice, and melted cheddar.
For a little extra heartiness, you can stir in 1 to 2 cups of cooked, diced chicken or leftover ham along with the broccoli. If you prefer a milder flavor, use a medium or mild cheddar instead of sharp, or mix in a bit of Monterey Jack for extra melt. To keep it vegetarian, simply swap the cream of chicken soup for cream of mushroom or cream of celery. If you like a bit of texture on top, crush a handful of buttery crackers or plain cornflakes and sprinkle them over the cheese before baking. For a stovetop-only version, skip the oven: let the rice, soup, milk, broccoli, and cheese mixture simmer on very low heat in a covered pan for 10 minutes, stirring now and then, until everything is hot, creamy, and the broccoli is tender. You can also use fresh broccoli florets—just chop them small and steam or microwave briefly until crisp-tender before stirring into the rice so they cook through in the same amount of time.
