Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the drained green beans, cream of mushroom soup, milk, soy sauce, garlic powder, salt, and pepper. Stir until well mixed.
Pour the mixture into a 1.5-quart baking dish and spread it evenly.
Bake in the preheated oven for 25 minutes.
Remove the casserole from the oven and stir in half of the French fried onions.
Top the casserole with the remaining French fried onions.
Return to the oven and bake for an additional 10 minutes, or until the onions are golden brown and crispy.
Let it cool for a few minutes before serving.