Preheat your oven to 350°F and lightly butter a 9x13-inch baking dish. While the oven heats, trim the fresh green beans and cut them into 2-inch pieces for even cooking throughout the casserole.

Melt butter in a large skillet over medium-high heat and sauté the sliced mushrooms until golden brown, about 5-7 minutes. Season with salt, pepper, and garlic powder, then transfer to a bowl and set aside for later layering.

In a large mixing bowl, whisk together the cream of mushroom soup, milk, soy sauce, Worcestershire sauce, paprika, and remaining seasonings until completely smooth. This creamy sauce base forms the foundation for the entire dish.

Gently fold the fresh green beans, sautéed mushrooms, and 1 1/2 cups of the French fried onions into the cream mixture, stirring carefully to avoid breaking the vegetables. Pour this combination into the prepared baking dish and spread evenly.

Mix the remaining 1 cup of fried onions with breadcrumbs and Parmesan cheese in a small bowl. Sprinkle this topping generously over the casserole to ensure a golden, crispy finish during baking.

Bake uncovered for 30-35 minutes until the casserole is bubbling around the edges and the top is golden brown. The thanksgiving green bean casserole crowd will smell incredible, filling your kitchen with savory aromas throughout cooking.

Remove from the oven and let rest for 5 minutes before serving. This brief resting period allows the sauce to set slightly for cleaner scoops.