First, butterfly each chicken breast and cut it into two even portions. Gently pound each piece until evenly thin, then season both sides with salt, black pepper, paprika, garlic powder, and onion powder. Coat each piece in flour, dip into the beaten eggs, and finally press firmly into the panko breadcrumbs until evenly coated.
Next, heat enough vegetable oil in a large frying pan over medium heat for shallow frying. Carefully fry the breaded chicken for 4–5 minutes per side, or until beautifully golden brown, crispy, and fully cooked through. Transfer the cooked schnitzels to a wire rack to keep them crispy while you prepare the pasta.
Meanwhile, bring a large pot of generously salted water to a boil and cook the pasta according to the package instructions until al dente. Before draining, reserve ½ cup of the pasta cooking water, then drain the pasta and set it aside.
Then, melt the butter in a large skillet over medium heat. Add the diced onion and sauté for 2–3 minutes until softened, then stir in the minced garlic and cook for another 30 seconds until fragrant. Add the sliced mushrooms and continue cooking until they become tender and lightly golden.
Afterwards, pour in the heavy cream and milk, stirring until well combined. If using grated cheese, stir it in until completely melted. Season the sauce with garlic powder, onion powder, mixed herbs, chicken powder, salt, and black pepper, then allow it to simmer gently for 2–3 minutes until smooth, creamy, and slightly thickened.
Next, add the cooked pasta directly into the creamy mushroom sauce and toss well until every piece is evenly coated. Gradually stir in a little reserved pasta water, if needed, until the sauce reaches a silky, glossy consistency that coats the pasta perfectly.
Finally, slice the crispy chicken schnitzel into strips and arrange it over the creamy garlic mushroom pasta. Finish with freshly grated Parmesan cheese and chopped parsley, then serve immediately while hot for the best flavour and texture.