01 - Preheat the oven to 350°F. Grease a 9x13-inch baking dish with cooking spray or butter.
02 - Bring a large pot of salted water to a boil. Add green beans and cook for 4-5 minutes until just tender. Drain and rinse under cold water to stop cooking.
03 - In a large bowl, whisk together cream of mushroom soup, milk, sour cream, garlic powder, onion powder, black pepper, and salt until smooth and well combined.
04 - Add green beans, cheddar cheese, and French fried onions to the sauce. Stir until all ingredients are evenly coated.
05 - Pour the green bean mixture into the prepared baking dish and spread into an even layer.
06 - In a small bowl, combine crushed Ritz crackers with melted butter. Mix until crackers are evenly coated.
07 - Sprinkle cracker mixture evenly over the casserole. Bake for 30-35 minutes until topping is golden brown and casserole is bubbling around edges.
08 - Remove from oven and let rest for 5 minutes to set before serving.