Preheat the oven to 350°F (175°C).
Trim and blanch the fresh green beans in boiling water for 5 minutes until crisp-tender. Drain and set aside.
In a large mixing bowl, combine the cream of mushroom soup, milk, soy sauce, and black pepper. Mix until smooth.
Add the blanched green beans to the sauce mixture and stir to coat evenly.
Transfer the mixture to a rectangular casserole dish, spreading it out evenly.
Bake uncovered for 25 minutes until hot and bubbling.
Remove from the oven and sprinkle the fried crispy onions evenly over the top.
Return to the oven and bake for an additional 5 minutes until the topping is golden brown and crispy.
Serve the casserole directly from the dish while warm.