Heat oven to 180C/fan 160C/gas 4.

Boil 600g rigatoni for 2 mins less time than stated on the pack.

To make the sauce, melt 50g butter in a saucepan and stir in 50g plain flour.

Cook for 1 min, then gradually stir in 600ml milk to make a thick white sauce.

Remove from the heat and stir in all but a handful of the 250g grated cheddar.

Drain the pasta, mix with the white sauce, two 160g drained cans tuna, one 330g drained can sweetcorn and a large handful of chopped parsley, then season.

Transfer to a baking dish and top with the rest of the grated cheddar.

Bake for 15-20 mins until the cheese on top is golden and starting to brown.