In a large pan over medium heat, melt the butter, then whisk in the flour and cook for 1–2 minutes until smooth and lightly golden. This creates the base for a rich, creamy sauce.
Whisk in the salt, pepper, garlic powder, and hot sauce, then slowly pour in the whole milk while stirring to keep the sauce smooth.
Add the Velveeta cheese and continue stirring until fully melted and the sauce is thick, glossy, and creamy.
Add the parboiled noodles to a greased baking dish, then layer in the gouda, mozzarella, cheddar, and remaining cup of whole milk.
Pour the cheese sauce over the noodles and mix thoroughly until everything is evenly coated, then finish with an extra sprinkle of shredded cheese on top.
Bake at 350°F for 30 minutes, or until the top cheese is fully melted and bubbling, then remove, rest briefly, and serve hot.
