Preheat the oven to 375°F [190°C]. Grease an oven safe casserole dish (8 cup, 8x8 or similar) with oil or butter and set aside.
Sauté sliced onions. Heat oil or butter in a small frying pan over medium heat. Once hot add the sliced onion and cook, stirring occasionally for 5-8 minutes until the onion has browned and is starting to become crispy. Remove from the heat and set aside.
1 small onion
Trim and blanch the green beans. Remove the tip and tail of the green beans. Bring a large pot of heavily salted water to a boil and add the green beans. Cook for about 3 minutes until the beans turn bright green and are just fork tender but still crisp. Drain the beans over a colander and transfer to a bowl with cold water to stop the cooking. Once cool drain the green beans and set aside.
1 ½ pounds green beans
Sauté mushrooms and spices. Heat butter in a large skillet over medium heat until melted and bubbling. If using, add the sliced mushroom and sauté until browned and soft. Add the Italian seasoning, onion, powder, garlic powder, black pepper, and salt to the pan and cook for 1 minute.
3 tablespoons butter, 1 cup sliced mushrooms, 1 teaspoon Italian seasoning, ½ teaspoon onion powder, ½ teaspoon garlic powder, ½ teaspoon black pepper, ½ teaspoon salt
Prepare the cream sauce. Add the heavy cream and cubed cream cheese to the skillet and bring to a simmer. Simmer, stirring occasionally until the cream cheese has melted and the sauce is smoothed hand thickened. Season to taste with salt and pepper.
1 cup heavy cream, 4 oz cream cheese
Coat blanched green beans in the cream sauce. Add the drained green beans to the skillet and toss to coat in the sauce. Transfer to the greased casserole dish in an even layer.
Bake the green beans. Top the green beans in the casserole dish with grated cheddar cheese. Bake at 375°F [190°C] for 20-25 minutes until the cheese has bubbled and starts to brown.
3 oz cheddar cheese
Add the crunchy topping. Crush the pork rinds using a food processor or by adding to a freezer bag and crushing with a rolling pin. Remove the casserole from the oven and add the pan fried onions, crushed pork rinds and parmesan cheese in an even layer. Return the casserole to the oven for 5-8 minutes until the topping is golden brown and crispy.
1 oz pork rinds, 4 tablespoons Parmesan
Cool and serve. Allow the casserole to cool for 5-8 minute before serving.