Heat oven to 350 F.

Bring a pot of water to boil and cook the egg noodles according to package directions. Meanwhile, make the rest of the casserole.

Heat a large saucepan over medium heat. Add the olive oil and butter. 

Once the butter is melted, add the onions and mushrooms, season with salt and garlic powder and cook until softened, about 8 to 10 minutes. Add the flour to the mushrooms and onions and cook for one minute, stirring continuously.

Slowly whisk in the milk followed by the chicken broth. Cook for 3 to 4 minutes, until the sauce has thickened.

Combine the sauce with the cooked noodles, tuna and 1 cup of the shredded cheddar cheese. 

Pour the mixture into a greased 9×13-inch pan and then top with the remaining cheese and crushed potato chips. Bake for 20 minutes, until bubbling and golden brown.

Serve immediately, topped with fresh chopped parsley. Enjoy!