Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish.
If using fresh broccoli, blanch in boiling water for 2–3 minutes until bright green, then drain. If using frozen, thaw and drain well.
In a large bowl, stir together the cream soup, cheddar cheese, sour cream, milk, garlic powder, onion powder, salt, and pepper until smooth.
Add the broccoli to the cheese mixture and toss to coat evenly.
Transfer the broccoli mixture to the prepared baking dish and spread it out evenly.
In a small bowl, mix the crushed crackers with melted butter. Sprinkle evenly over the top of the casserole.
Bake for 25–30 minutes, or until the casserole is hot and bubbly and the topping is golden brown.
Let cool slightly before serving.