In a large mixing bowl, combine the cream of mushroom soup, sour cream, soy sauce, garlic powder, black pepper, and salt. Stir until smooth.
Fold in the drained green beans and about half of the crispy fried onions, mixing until everything is well coated.
Add the shredded cheddar cheese to the mixture, reserving a little cheese for topping.
Transfer the mixture to a greased 9x13 inch baking dish, spreading it out evenly.
Sprinkle the reserved cheddar cheese over the top of the casserole.
Bake in the preheated oven for 25-30 minutes, or until the casserole is hot and bubbly.
Remove from the oven and top with the remaining crispy fried onions. Return to the oven for an additional 5-10 minutes, until the onions are golden brown.
Let it sit for about 5 minutes before serving to allow it to set slightly.
Notes
For a non-vegetarian twist, add cooked and crumbled bacon.