Preheat the oven to 220C (200 fan/ 425F/ Gas 7).
Bring a pan of salted water to the boil and cook the macaroni to al dente. Reserve a cup of pasta water before draining the pasta.
275 g Macaroni
While the pasta is cooking, heat the butter in a large saucepan on a medium heat until melted and then add the flour. Stir with a wooden spoon for 2 minutes.
50 g Butter, 50 g Plain Flour
Turn up the heat to high and gradually whisk in the milk, stirring until the sauce starts to bubble and thicken. it should coat the back of a wooden spoon. Take the white sauce off the heat
600 ml Milk
Stir in the grated cheddar, Parmesan, Dijon mustard, salt and pepper.
1 teaspoon Dijon Mustard, 220 g Extra Mature Cheddar, 20 g Parmesan, ½ teaspoon Salt, ¼ teaspoon Black Pepper
Mix in the cooked pasta and as much pasta cooking water as you need to create a smooth and glossy sauce.
Pour the macaroni cheese into a 1.5 litre baking dish, sprinkle with the Parmesan cheese for the topping, and bake in the oven for 10-15 minutes until golden and bubbling.
20 g Parmesan