Prepare the Green Beans

1. Preheat Oven: Preheat the oven to 350°F (175°C). Grease a 9×13-inch baking dish.
2. Blanch Fresh Green Beans (If Using): Bring a pot of salted water to a boil. Add green beans and cook for 3-4 minutes. Drain and immediately transfer to ice water to stop cooking.

Make the Casserole Base

1. Mix Sauce Ingredients: In a large bowl, combine the cream of mushroom soup, milk, sour cream, soy sauce, black pepper, garlic powder, and onion powder. Mix until well blended.
2. Add Green Beans: Stir in the cooked (or thawed frozen) green beans until they are well coated with the sauce.

Assemble the Casserole

1. Pour Into Baking Dish: Transfer the green bean mixture into the prepared baking dish.
2. Add Toppings: Sprinkle half of the crispy fried onions over the top. If using, add the cheddar cheese and bacon.

Bake

1. Initial Baking: Bake in the preheated oven for 25 minutes.
2. Add Remaining Onions: Remove the casserole from the oven and sprinkle the remaining crispy fried onions on top.
3. Bake Again: Return to the oven and bake for an additional 5-10 minutes, or until the onions are golden brown.
4. Cool Slightly: Allow the casserole to cool for a few minutes before serving.