Brown the Ground Beef: In a large skillet, brown the ground beef over medium heat and drain the grease. Use a skillet large enough to hold the beef, noodles, and liquid together, and one with a lid, since you will cover it later. Break the meat into small crumbles as it cooks so it spreads evenly through the finished dish. Draining the fat keeps the sauce from turning greasy.
Add Everything Except the Cheese: Add all of the remaining ingredients to the skillet, except for the cheese, and stir to combine. That means the macaroni, hot water, milk, cornstarch, paprika, onion powder, garlic powder, mustard powder, salt, and pepper. Stir well so the cornstarch and spices dissolve into the liquid instead of clumping, and so the macaroni is submerged.
Boil, Cover, and Simmer: Bring the mixture to a boil, cover, and reduce the heat to a simmer. Let it cook for 12 minutes. Check on it once or twice to stir, since pasta can settle and stick to the bottom of the pan. The noodles are done when they are tender, and the sauce will have thickened as they cook.
Add the Cheese and Rest: Remove the skillet from the heat and stir in the cheese. Cover and let it sit for 2 minutes, then stir again to combine. Serve and enjoy. Adding the cheese off the heat helps it melt gently into the sauce without turning grainy or oily. The short rest lets it melt fully, and the sauce thickens a little more as it stands.