• Pre-heat the oven: 180°C (160°C fan)

  The cheese sauce and pasta need to be cooked at the same time.

Cheese Sauce

• Put the milk, cornflour, butter, onion powder, mustard powder and cayenne into a medium saucepan and place it over a gentle heat.
• Using a balloon whisk, whisk continuously as the butter melts and the sauce slowly comes up to a gentle simmer. The sauce will thicken quite suddenly, so keep whisking until it is smooth, glossy and coats the back of a spoon.
• Turn the heat right down and let it simmer very gently for 8–10 minutes, whisking from time to time so it does not catch. This cooks out the cornflour and gives the sauce a rounded, savoury flavour.
• Add the Cheddar and Parmesan, whisking until fully melted and smooth. Season with salt, freshly milled black pepper and a little freshly grated nutmeg. Taste and adjust the seasoning if needed.

Pasta

• Cook the macaroni in well-salted boiling water until just tender. Drain well, but do not rinse.

Assemble and bake

• Stir the hot pasta straight into the cheese sauce until evenly coated.
• Transfer to a lightly buttered oven dish, scatter with a little extra grated parmesan cheese and sprinkle with breadcrumbs. Finally add a few small knobs of butter
• Bake at 180 °C (160 °C fan) for 20–25 minutes, until bubbling and lightly golden on top. Let it stand for a few minutes before serving so it thickens slightly while staying creamy.