Preheat your oven to 350°F (175°C).

In a large pot, bring salted water to a boil. Add green beans and blanch for 4–5 minutes. Transfer to ice water, then drain.

If using fresh mushrooms, sauté them in olive oil over medium heat for 5–7 minutes until tender.

In a mixing bowl, combine cream of mushroom soup, sour cream, milk, Worcestershire sauce, garlic powder, onion powder, and salt and pepper. Whisk until smooth.

Fold in mushrooms, blanched green beans, and fried onions into the sauce, stirring gently.

Transfer the mixture to a greased baking dish and top with shredded cheddar cheese.

Bake for 25–30 minutes until bubbling and the cheese is melted and golden.

Sprinkle additional fried onions on top and bake for another 5–10 minutes until crispy.

Let it sit for about 10 minutes before serving.