Preheat your oven to 350°F (175°C).
Drain the canned green beans or prepare fresh green beans by washing and cutting them into bite-sized pieces.
In a large mixing bowl, combine the cream of mushroom soup, milk, soy sauce, garlic powder, and black pepper. Stir until smooth.
Fold the drained green beans into the creamy sauce. If using, add shredded cheddar cheese and mix until well coated.
Fold in 1 cup of French fried onions and pour the mixture into a greased 9x13-inch baking dish. Spread evenly and top with the remaining 1/2 cup of French fried onions.
Bake for 25 minutes, then stir gently and return to the oven for an additional 10-15 minutes until the onions are golden brown and the casserole is bubbly.
Let the casserole cool for a few minutes before serving.