Bring 8 cups water to a boil in a large saucepan; add the trimmed green beans to the water. Cook the beans, uncovered, for three to four minutes until they are bright green and crisp-tender. Drain the green beans and set them aside.
In a large bowl, stir together the cream of mushroom soups, milk, soy sauce and pepper until everything is well combined. Stir the parcooked green beans into the sauce.
Preheat the oven to 350°F. Spoon half the green bean mixture into a 13x9-inch baking dish and spread it into an even layer. Then, layer half the french-fried onions over the bean layer. Spoon in the rest of the green bean mixture, and finish with the rest of the french-fried onions over the top.
Slide the casserole into the oven and bake at 350°, uncovered, for 30 to 35 minutes, until it's hot all the way through and the onion topping is browned and crispy. Serve warm.
