Preheat your oven to 350°F (175°C).
Bring a large pot of water to a boil. Add the green beans and cook for about 5 minutes, until they are crisp-tender. Drain the beans and transfer them to a large mixing bowl.
In a separate bowl, mix together the cream of mushroom soup, milk, soy sauce, and black pepper until well combined.
Pour the soup mixture over the green beans and stir until the beans are evenly coated.
Transfer the green bean mixture to a greased baking dish, spreading it out evenly.
Bake the casserole in the preheated oven for 25 minutes, or until it is hot and bubbly.
Remove the casserole from the oven and sprinkle the crispy fried onions evenly over the top.