Preheat the oven to 350°F (175°C).
Blanch the green beans in boiling water for 3 minutes, then drain and rinse in cold water.
In a large mixing bowl, combine the sour cream, cream of mushroom soup, cheddar cheese, garlic powder, and seasoning.
Add the blanched green beans to the mixture and stir until well coated.
Transfer the mixture to a greased baking dish and spread evenly.
Sprinkle French fried onions over the top of the casserole.
Bake for 30-35 minutes or until bubbly and golden brown.
Serve hot, and enjoy your Southern green bean casserole!