If there's two things the kids love, it's mac-and-cheese and burgers!
Follow the package directions to cook the pasta, but leave out salt and fat. Drain the water out.
Heat a big skillet over medium heat. Add beef, onion, Worcestershire, and mustard and cook while stirring often until the meat's done, around 5 minutes. Transfer everything to a bowl and stir in the tomatoes.
Whisk together milk and flour in a separate bowl. Pour the mixture into the skillet and bring it to a boil over high. Add the cheeses and stir that mess until the cheeses melt. Take it off the heat and stir in the pasta and meat mixture. Top it with parsley, salt, and pepper.