Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish with nonstick cooking spray.

Steam 6 cups of broccoli florets in a steamer basket for 3 minutes until bright green and tender-crisp, then drain well.

In a large mixing bowl, combine 10.5 ounces condensed cream of mushroom soup, 1 cup sour cream, 0.25 cup melted butter, 0.5 teaspoon garlic powder, 0.5 teaspoon onion powder, 0.5 teaspoon salt, and 0.25 teaspoon black pepper.

Fold the drained broccoli florets and 1.5 cups of shredded sharp cheddar cheese into the soup mixture until evenly coated.

Transfer the broccoli mixture into the prepared baking dish and spread it into an even layer using a spatula.

Sprinkle the remaining 0.5 cup of shredded sharp cheddar cheese over the top of the casserole.

In a small mixing bowl, stir together 1 cup crushed Ritz crackers and the remaining 0.25 cup melted butter, then scatter the crumbs evenly over the cheese.

Bake for 30 minutes until the edges are bubbling and the topping is golden brown, then let rest 5 minutes before serving.