01 - Bring a large pot of salted water to a rolling boil. Add the egg noodles and cook according to package instructions until al dente. Drain through a colander and set aside.
02 - While the noodles cook, melt the butter in a large skillet over medium heat. Add the chopped onion and sauté until soft and translucent, about 3 to 4 minutes. Add the minced garlic and cook for another 30 seconds until fragrant.
03 - Sprinkle the flour over the onion mixture, stirring constantly for 1 minute to form a smooth roux and cook off the raw flour taste.
04 - Gradually whisk in the milk and broth, stirring until completely smooth. Bring the mixture to a gentle simmer and cook for 3 to 4 minutes, or until the sauce has slightly thickened.
05 - Stir in the heavy cream, salt, pepper, and garlic powder. Continue cooking for 2 more minutes, then add the grated Parmesan cheese, stirring until fully melted and the sauce is creamy and smooth.
06 - Add the cooked egg noodles to the skillet, tossing gently to coat them evenly with the cream sauce. Taste and adjust seasoning with additional salt and pepper as needed.
07 - Serve immediately, garnished with chopped fresh parsley and extra Parmesan cheese if desired. Pairs well with steamed green beans or a simple green salad.