01 -
Preheat oven to 350°F.
02 -
In a large mixing bowl, whisk together condensed cream of mushroom soup, whole milk, salt, and black pepper until smooth.
03 -
Fold green beans and half of the French fried onions into the soup mixture until all vegetables are fully coated.
04 -
Transfer the green bean mixture to a lightly greased baking dish, spreading evenly.
05 -
Bake uncovered for 25 minutes on the center rack.
06 -
Scatter the remaining French fried onions evenly over the casserole and bake for an additional 10 minutes until topping is crisp and golden.