Preheat the oven to 350°F (175°C).

Blanch the green beans in salted boiling water for 3-5 minutes, then drain and rinse with cold water.

In a large bowl, combine the cream of mushroom soup, milk, soy sauce, garlic powder, and black pepper until smooth.

Add the blanched green beans and 1 cup of fried onions to the soup mixture, stirring to coat evenly.

Transfer the mixture to a greased 2-quart baking dish and spread it out evenly.

Bake in the preheated oven for 25 minutes, until heated through.

Sprinkle the remaining fried onions on top of the casserole and return to the oven.

Bake for an additional 10-15 minutes, until the onions are golden brown.

Remove from the oven and allow to cool for a few minutes before serving.