Pre heat the oven to 190°C/375°F. Butter a medium size oven proof dish and set aside.
Melt 25g of the butter and mix with the breadcrumbs and 2tsp of the bacon seasoning and set aside.
In medium saucepan, melt 3 tablespoons of butter, add the flour, cook and stir for about a minute to form a roux.
In a separate medium heavy based pan, bring the milk to the boil.
Pour the hot milk into the hot flour-butter mixture gradually, whisking continuously to remove all the lumps. Continue cooking the mixture, constantly stirring, on a medium heat until the mixture bubbles and thickens – about 1 or 2 minutes.
Remove the pan from the heat. Add the remaining seasoning, nutmeg, black pepper, ¾ of the grated cheddar and 2/3 of the parmesan. Stir well until all the cheese is melted and the sauce has a smooth consistency. Set aside.
Bring a large saucepan with water to the boil. Add the macaroni, cook 3 minutes less than indicated in the manufacturer’s directions, so that the pasta is still undercooked inside (the pasta will continue cooking as it bakes in step 10).
Transfer the macaroni to a colander and rinse under cold running water. Running the pasta under cold water will stop the pasta from cooking any further. Drain well then add the macaroni to the cheese sauce.
Pour the cheesy pasta into the buttered ovenproof dish. Sprinkle the remaining cheeses over the top along with the breadcrumbs
Bake for 30 minutes, until browned on top.
Best served straight away with a crisp salad and rustic bread.