01 - Bring a large pot of salted water to a rolling boil. Add the wide egg noodles and cook according to package directions until al dente. Drain thoroughly in a colander and set aside.
02 - While the noodles cook, melt the butter in a large skillet over medium heat. Add the finely chopped onion and sauté until soft and translucent, about 3 to 4 minutes. Add the minced garlic and cook for an additional 30 seconds until fragrant.
03 - Sprinkle the all-purpose flour over the onion and garlic mixture. Stir constantly for 1 minute to form a smooth roux and cook off the raw flour taste.
04 - Gradually whisk in the whole milk and broth, stirring until completely smooth with no lumps. Bring the mixture to a gentle simmer and cook for 3 to 4 minutes, stirring occasionally, until the sauce has slightly thickened.
05 - Stir in the heavy cream, salt, black pepper, and garlic powder. Continue cooking for 2 more minutes, then add the grated Parmesan cheese. Stir continuously until the cheese is fully melted and the sauce is creamy and smooth.
06 - Add the drained egg noodles to the skillet. Toss gently but thoroughly to coat every noodle evenly with the creamy sauce.
07 - Taste the finished dish and adjust the salt and pepper seasoning as needed.
08 - Transfer to serving dishes immediately. Garnish with chopped fresh parsley and an extra sprinkle of Parmesan cheese if desired.