Preheat your oven to 350°F (175°C).

Blanch the green beans in salted boiling water for 4-5 minutes. Drain and cool in ice water.

Sauté fresh mushrooms in olive oil for 5-7 minutes until tender (skip if using canned).

In a bowl, mix cream of mushroom soup, sour cream, and milk. Add Worcestershire sauce, garlic powder, onion powder, salt, and pepper.

Fold in the blanched green beans, mushrooms, and ½ cup fried onions into the creamy mixture.

Transfer to a greased 9x13 inch baking dish and spread evenly.

Sprinkle shredded cheddar cheese over the top.

Bake for 25-30 minutes until bubbling and cheese is golden.

Top with additional fried onions and bake for another 5-10 minutes.

Let the casserole rest for 10 minutes before serving.