Preheat oven to 200˚C (180˚C fan forced). Place milk, butter, flour, mustard and garlic in a medium saucepan over a MEDIUM heat and cook stirring constantly for 5-8 minutes or until sauce thickens and is smooth.
Fold 1 ¾ cups of tasty cheese through the sauce followed by the cooked pasta. Spoon into a lightly greased oven proof dish.
Place remaining tasty cheese, Parmesan cheese and the Twisties into the bowl of a food processor. Pulse, once or twice, processing until Twisties are roughly crushed. Sprinkle crumb mixture over the mac n cheese.