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.