Bring a saucepan of water to the boil, and then add the macaroni. Cook for about 10-12 minutes until al dente.

Grate the cheese and slice the tomato.

While the pasta is cooking, make the sauce: Place the butter, flour and milk into a small saucepan, bring the sauce to a simmer, whisking it all the time until it has thickened, reduce the heat and allow to simmer for 2 minutes and then stir in 75g of the grated cheese.

Preheat the grill.

Drain the boiling hot water away from the macaroni into a colander in the sink.

Stir the drained macaroni into the cheese sauce and add a few twists of black pepper.

Pour the macaroni into an over proof dish or foil tray.

Arrange the tomato slices over the macaroni.

Sprinkle over the remaining cheese.

Place under the hot grill until the cheese is bubbling and golden brown.