In a large pot, bring salted water to a boil. Add the green beans and blanch for 3-4 minutes until bright green and slightly tender. Drain and transfer them immediately to an ice water bath to stop the cooking. Drain again and set aside.
In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add onions and garlic, sautéing until the onions become translucent (about 3-4 minutes). Then add the mushrooms and cook for an additional 5 minutes until they are tender and browned.
In a large bowl, combine the cream of mushroom soup, vegetable broth, soy sauce, Worcestershire sauce, black pepper, and salt. Mix until smooth.
Stir the blanched green beans, sautéed mushroom mixture, and shredded cheddar cheese into the bowl with the soup mixture. Fold it gently until well combined.
Pour the green bean mixture into a greased 9x13 inch baking dish, spreading it out evenly.
In a small bowl, combine panko breadcrumbs, remaining fried onion strings, garlic powder, paprika, and 1 tablespoon of olive oil. Mix until the panko is well coated.
Sprinkle the crunchy topping mixture evenly over the green bean casserole.
Place the baking dish in the preheated oven and bake for 25-30 minutes, or until the casserole is bubbly and the topping is golden brown.
Remove from the oven, let it cool for a few minutes, and serve warm.
Notes
Top with extra fried onion strings for added crunch.