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 through 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, stirring 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 and free of lumps. 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, black 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 drained egg noodles to the skillet, tossing gently to coat them evenly with the creamy sauce. Taste and adjust seasoning with additional salt or pepper as needed.
07 - Transfer to serving bowls immediately. Garnish with chopped fresh parsley and an extra sprinkle of Parmesan cheese if desired.